81686889315 has 40 divisors (see below), whose sum is σ = 146462432688. Its totient is φ = 43557082560.

The previous prime is 81686889311. The next prime is 81686889337. The reversal of 81686889315 is 51398868618.

It is not a de Polignac number, because 81686889315 - 2² = 81686889311 is a prime.

It is a super-2 number, since 2×81686889315² (a number of 23 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81686889311) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 2160564 + ... + 2198046.

Almost surely, 2^81686889315 is an apocalyptic number.

81686889315 is a deficient number, since it is larger than the sum of its proper divisors (64775543373).

81686889315 is a wasteful number, since it uses less digits than its factorization.

81686889315 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42881 (or 42872 counting only the distinct ones).

The product of its digits is 19906560, while the sum is 63.

The spelling of 81686889315 in words is "eighty-one billion, six hundred eighty-six million, eight hundred eighty-nine thousand, three hundred fifteen".