81261256 has 16 divisors (see below), whose sum is σ = 152461440. Its totient is φ = 40604880.

The previous prime is 81261251. The next prime is 81261281. The reversal of 81261256 is 65216218.

It is not an unprimeable number, because it can be changed into a prime (81261251) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 20301 + ... + 23971.

It is an arithmetic number, because the mean of its divisors is an integer number (9528840).

Almost surely, 2^81261256 is an apocalyptic number.

It is an amenable number.

81261256 is a deficient number, since it is larger than the sum of its proper divisors (71200184).

81261256 is a wasteful number, since it uses less digits than its factorization.

81261256 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6444 (or 6440 counting only the distinct ones).

The product of its digits is 5760, while the sum is 31.

The square root of 81261256 is about 9014.5025375780. The cubic root of 81261256 is about 433.1395525415.

The spelling of 81261256 in words is "eighty-one million, two hundred sixty-one thousand, two hundred fifty-six".