81689892 has 24 divisors (see below), whose sum is σ = 200642400. Its totient is φ = 25796736.

The previous prime is 81689869. The next prime is 81689921. The reversal of 81689892 is 29898618.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 178917 + ... + 179372.

It is an arithmetic number, because the mean of its divisors is an integer number (8360100).

Almost surely, 2^81689892 is an apocalyptic number.

It is an amenable number.

81689892 is an abundant number, since it is smaller than the sum of its proper divisors (118952508).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81689892 is a wasteful number, since it uses less digits than its factorization.

81689892 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 358315 (or 358313 counting only the distinct ones).

The product of its digits is 497664, while the sum is 51.

The square root of 81689892 is about 9038.2460687901. The cubic root of 81689892 is about 433.8997906915.

The spelling of 81689892 in words is "eighty-one million, six hundred eighty-nine thousand, eight hundred ninety-two".