81907597 has 4 divisors (see below), whose sum is σ = 82083456. Its totient is φ = 81731740.

The previous prime is 81907589. The next prime is 81907607. The reversal of 81907597 is 79570918.

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.

It is a cyclic number.

It is not a de Polignac number, because 81907597 - 2³ = 81907589 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 (81907097) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 87229 + ... + 88162.

It is an arithmetic number, because the mean of its divisors is an integer number (20520864).

Almost surely, 2^81907597 is an apocalyptic number.

It is an amenable number.

81907597 is a deficient number, since it is larger than the sum of its proper divisors (175859).

81907597 is a wasteful number, since it uses less digits than its factorization.

81907597 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 175858.

The product of its (nonzero) digits is 158760, while the sum is 46.

The square root of 81907597 is about 9050.2815978289. The cubic root of 81907597 is about 434.2848989801.

The spelling of 81907597 in words is "eighty-one million, nine hundred seven thousand, five hundred ninety-seven".