81765776 has 10 divisors (see below), whose sum is σ = 158421222. Its totient is φ = 40882880.

The previous prime is 81765773. The next prime is 81765781. The reversal of 81765776 is 67756718.

It can be written as a sum of positive squares in only one way, i.e., 67897600 + 13868176 = 8240^2 + 3724^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 81765776.

It is not an unprimeable number, because it can be changed into a prime (81765773) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2555165 + ... + 2555196.

Almost surely, 2^81765776 is an apocalyptic number.

It is an amenable number.

81765776 is a deficient number, since it is larger than the sum of its proper divisors (76655446).

81765776 is a wasteful number, since it uses less digits than its factorization.

81765776 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5110369 (or 5110363 counting only the distinct ones).

The product of its digits is 493920, while the sum is 47.

The square root of 81765776 is about 9042.4430327207. The cubic root of 81765776 is about 434.0341029499.

The spelling of 81765776 in words is "eighty-one million, seven hundred sixty-five thousand, seven hundred seventy-six".