81751964 has 24 divisors (see below), whose sum is σ = 163699200. Its totient is φ = 34994736.

The previous prime is 81751961. The next prime is 81751973. The reversal of 81751964 is 46915718.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81751961) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 38129 + ... + 40215.

It is an arithmetic number, because the mean of its divisors is an integer number (6820800).

Almost surely, 2^81751964 is an apocalyptic number.

It is an amenable number.

81751964 is an abundant number, since it is smaller than the sum of its proper divisors (81947236).

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

81751964 is a wasteful number, since it uses less digits than its factorization.

81751964 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3497 (or 3495 counting only the distinct ones).

The product of its digits is 60480, while the sum is 41.

The square root of 81751964 is about 9041.6792688084. The cubic root of 81751964 is about 434.0096623388.

The spelling of 81751964 in words is "eighty-one million, seven hundred fifty-one thousand, nine hundred sixty-four".