81775868 has 24 divisors (see below), whose sum is σ = 145969824. Its totient is φ = 40075200.

The previous prime is 81775801. The next prime is 81775871. The reversal of 81775868 is 86857718.

It is a congruent number.

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, 112121 + ... + 112847.

It is an arithmetic number, because the mean of its divisors is an integer number (6082076).

Almost surely, 2^81775868 is an apocalyptic number.

It is an amenable number.

81775868 is a deficient number, since it is larger than the sum of its proper divisors (64193956).

81775868 is a wasteful number, since it uses less digits than its factorization.

81775868 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1253 (or 1251 counting only the distinct ones).

The product of its digits is 752640, while the sum is 50.

The square root of 81775868 is about 9043.0010505363. The cubic root of 81775868 is about 434.0519592063.

The spelling of 81775868 in words is "eighty-one million, seven hundred seventy-five thousand, eight hundred sixty-eight".