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72191297 = 187738461
BaseRepresentation
bin1000100110110…
…00110101000001
312000211200211202
410103120311001
5121440110142
611055150545
71534421153
oct423306501
9160750752
1072191297
1137828432
1220215455
1311c58059
149832ad3
156510032
hex44d8d41

72191297 has 4 divisors (see below), whose sum is σ = 72231636. Its totient is φ = 72150960.

The previous prime is 72191291. The next prime is 72191321. The reversal of 72191297 is 79219127.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 79219127 = 136093779.

It can be written as a sum of positive squares in 2 ways, for example, as 27888961 + 44302336 = 5281^2 + 6656^2 .

It is a cyclic number.

It is not a de Polignac number, because 72191297 - 212 = 72187201 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 72191297.

It is not an unprimeable number, because it can be changed into a prime (72191291) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 17354 + ... + 21107.

It is an arithmetic number, because the mean of its divisors is an integer number (18057909).

Almost surely, 272191297 is an apocalyptic number.

It is an amenable number.

72191297 is a deficient number, since it is larger than the sum of its proper divisors (40339).

72191297 is a wasteful number, since it uses less digits than its factorization.

72191297 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40338.

The product of its digits is 15876, while the sum is 38.

The square root of 72191297 is about 8496.5461806548. The cubic root of 72191297 is about 416.3848774884.

The spelling of 72191297 in words is "seventy-two million, one hundred ninety-one thousand, two hundred ninety-seven".

Divisors: 1 1877 38461 72191297