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71993837 = 419171823
BaseRepresentation
bin1000100101010…
…00100111101101
312000110122222102
410102220213231
5121412300322
611051024445
71532636366
oct422504755
9160418872
1071993837
1137703043
122013b125
1311bb9206
1497c0b6d
1564c1792
hex44a89ed

71993837 has 4 divisors (see below), whose sum is σ = 72166080. Its totient is φ = 71821596.

The previous prime is 71993819. The next prime is 71993843. The reversal of 71993837 is 73839917.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 73839917 = 604712211.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2k-71993837 is a prime.

It is a super-2 number, since 2×719938372 = 10366225131965138, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 71993791 and 71993800.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (71995837) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 85493 + ... + 86330.

It is an arithmetic number, because the mean of its divisors is an integer number (18041520).

Almost surely, 271993837 is an apocalyptic number.

It is an amenable number.

71993837 is a deficient number, since it is larger than the sum of its proper divisors (172243).

71993837 is a wasteful number, since it uses less digits than its factorization.

71993837 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 172242.

The product of its digits is 285768, while the sum is 47.

The square root of 71993837 is about 8484.9182082092. The cubic root of 71993837 is about 416.0048943119.

The spelling of 71993837 in words is "seventy-one million, nine hundred ninety-three thousand, eight hundred thirty-seven".

Divisors: 1 419 171823 71993837