81210568 has 16 divisors (see below), whose sum is σ = 153434160. Its totient is φ = 40294800.

The previous prime is 81210511. The next prime is 81210587. The reversal of 81210568 is 86501218.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 37698 + ... + 39793.

It is an arithmetic number, because the mean of its divisors is an integer number (9589635).

Almost surely, 2^81210568 is an apocalyptic number.

It is an amenable number.

81210568 is a deficient number, since it is larger than the sum of its proper divisors (72223592).

81210568 is a wasteful number, since it uses less digits than its factorization.

81210568 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 77628 (or 77624 counting only the distinct ones).

The product of its (nonzero) digits is 3840, while the sum is 31.

The square root of 81210568 is about 9011.6906293991. The cubic root of 81210568 is about 433.0494745830.

It can be divided in two parts, 8 and 1210568, that multiplied together give a square (9684544 = 3112²).

The spelling of 81210568 in words is "eighty-one million, two hundred ten thousand, five hundred sixty-eight".