81651256 has 8 divisors (see below), whose sum is σ = 153096120. Its totient is φ = 40825624.

The previous prime is 81651253. The next prime is 81651263. The reversal of 81651256 is 65215618.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (8).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81651253) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5103196 + ... + 5103211.

It is an arithmetic number, because the mean of its divisors is an integer number (19137015).

Almost surely, 2^81651256 is an apocalyptic number.

It is an amenable number.

81651256 is a deficient number, since it is larger than the sum of its proper divisors (71444864).

81651256 is a wasteful number, since it uses less digits than its factorization.

81651256 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10206413 (or 10206409 counting only the distinct ones).

The product of its digits is 14400, while the sum is 34.

The square root of 81651256 is about 9036.1084544178. The cubic root of 81651256 is about 433.8313742468.

The spelling of 81651256 in words is "eighty-one million, six hundred fifty-one thousand, two hundred fifty-six".