81770856 has 16 divisors (see below), whose sum is σ = 204427200. Its totient is φ = 27256944.

The previous prime is 81770837. The next prime is 81770881. The reversal of 81770856 is 65807718.

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, 1703536 + ... + 1703583.

It is an arithmetic number, because the mean of its divisors is an integer number (12776700).

Almost surely, 2^81770856 is an apocalyptic number.

It is an amenable number.

81770856 is an abundant number, since it is smaller than the sum of its proper divisors (122656344).

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

81770856 is a wasteful number, since it uses less digits than its factorization.

81770856 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3407128 (or 3407124 counting only the distinct ones).

The product of its (nonzero) digits is 94080, while the sum is 42.

The square root of 81770856 is about 9042.7239258976. The cubic root of 81770856 is about 434.0430914196.

The spelling of 81770856 in words is "eighty-one million, seven hundred seventy thousand, eight hundred fifty-six".