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3999991 = 19972003
BaseRepresentation
bin1111010000100011110111
321112012221211
433100203313
52010444431
6221422251
745666532
oct17204367
97465854
103999991
112292286
12140a987
13aa0878
14761a19
155402b1
hex3d08f7

3999991 has 4 divisors (see below), whose sum is σ = 4003992. Its totient is φ = 3995992.

The previous prime is 3999971. The next prime is 4000037. The reversal of 3999991 is 1999993.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 3999991 - 221 = 1902839 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3999901) 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, 996 + ... + 2998.

It is an arithmetic number, because the mean of its divisors is an integer number (1000998).

Almost surely, 23999991 is an apocalyptic number.

3999991 is a deficient number, since it is larger than the sum of its proper divisors (4001).

3999991 is a wasteful number, since it uses less digits than its factorization.

3999991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4000.

The product of its digits is 177147, while the sum is 49.

The square root of 3999991 is about 1999.9977499987. The cubic root of 3999991 is about 158.7399861417.

The spelling of 3999991 in words is "three million, nine hundred ninety-nine thousand, nine hundred ninety-one".

Divisors: 1 1997 2003 3999991