81697255516 has 6 divisors (see below), whose sum is σ = 142970197160. Its totient is φ = 40848627756.

The previous prime is 81697255511. The next prime is 81697255529. The reversal of 81697255516 is 61555279618.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81697255511) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10212156936 + ... + 10212156943.

Almost surely, 2^81697255516 is an apocalyptic number.

It is an amenable number.

81697255516 is a deficient number, since it is larger than the sum of its proper divisors (61272941644).

81697255516 is a wasteful number, since it uses less digits than its factorization.

81697255516 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20424313883 (or 20424313881 counting only the distinct ones).

The product of its digits is 4536000, while the sum is 55.

The spelling of 81697255516 in words is "eighty-one billion, six hundred ninety-seven million, two hundred fifty-five thousand, five hundred sixteen".