81256536 has 48 divisors (see below), whose sum is σ = 220507560. Its totient is φ = 27031680.

The previous prime is 81256531. The next prime is 81256537. The reversal of 81256536 is 63565218.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 81256536.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81256531) by changing a digit.

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 11 ways as a sum of consecutive naturals, for example, 54051 + ... + 55533.

Almost surely, 2^81256536 is an apocalyptic number.

It is an amenable number.

81256536 is an abundant number, since it is smaller than the sum of its proper divisors (139251024).

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

81256536 is a wasteful number, since it uses less digits than its factorization.

81256536 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2256 (or 2249 counting only the distinct ones).

The product of its digits is 43200, while the sum is 36.

The square root of 81256536 is about 9014.2407334173. The cubic root of 81256536 is about 433.1311661822.

The spelling of 81256536 in words is "eighty-one million, two hundred fifty-six thousand, five hundred thirty-six".