81768776 has 16 divisors (see below), whose sum is σ = 162335340. Its totient is φ = 38479360.

The previous prime is 81768763. The next prime is 81768781. The reversal of 81768776 is 67786718.

It can be written as a sum of positive squares in 2 ways, for example, as 80820100 + 948676 = 8990^2 + 974^2 .

It is a super-2 number, since 2×81768776² = 13372265457076352, which contains 22 as substring.

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, 300485 + ... + 300756.

Almost surely, 2^81768776 is an apocalyptic number.

It is an amenable number.

81768776 is a deficient number, since it is larger than the sum of its proper divisors (80566564).

81768776 is a wasteful number, since it uses less digits than its factorization.

81768776 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 601264 (or 601260 counting only the distinct ones).

The product of its digits is 790272, while the sum is 50.

The square root of 81768776 is about 9042.6089155730. The cubic root of 81768776 is about 434.0394111463.

The spelling of 81768776 in words is "eighty-one million, seven hundred sixty-eight thousand, seven hundred seventy-six".