81751760 has 20 divisors (see below), whose sum is σ = 190073028. Its totient is φ = 32700672.

The previous prime is 81751711. The next prime is 81751777. The reversal of 81751760 is 6715718.

It can be written as a sum of positive squares in 2 ways, for example, as 47224384 + 34527376 = 6872^2 + 5876^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is a hoax number, since the sum of its digits (35) coincides with the sum of the digits of its distinct prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 81751760.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 510869 + ... + 511028.

Almost surely, 2^81751760 is an apocalyptic number.

81751760 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

81751760 is an abundant number, since it is smaller than the sum of its proper divisors (108321268).

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

81751760 is a wasteful number, since it uses less digits than its factorization.

81751760 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1021910 (or 1021904 counting only the distinct ones).

The product of its (nonzero) digits is 11760, while the sum is 35.

The square root of 81751760 is about 9041.6679877111. The cubic root of 81751760 is about 434.0093013360.

The spelling of 81751760 in words is "eighty-one million, seven hundred fifty-one thousand, seven hundred sixty".