81697642215 has 32 divisors (see below), whose sum is σ = 149443176960. Its totient is φ = 37334193024.

The previous prime is 81697642189. The next prime is 81697642231. The reversal of 81697642215 is 51224679618.

It is not a de Polignac number, because 81697642215 - 2⁷ = 81697642087 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 160756 + ... + 435014.

It is an arithmetic number, because the mean of its divisors is an integer number (4670099280).

Almost surely, 2^81697642215 is an apocalyptic number.

81697642215 is a deficient number, since it is larger than the sum of its proper divisors (67745534745).

81697642215 is a wasteful number, since it uses less digits than its factorization.

81697642215 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 277111.

The product of its digits is 1451520, while the sum is 51.

The spelling of 81697642215 in words is "eighty-one billion, six hundred ninety-seven million, six hundred forty-two thousand, two hundred fifteen".