81521274 has 16 divisors (see below), whose sum is σ = 163338912. Its totient is φ = 27124368.

The previous prime is 81521213. The next prime is 81521281. The reversal of 81521274 is 47212518.

It is a super-2 number, since 2×81521274² = 13291436229166152, which contains 22 as substring.

It is a Curzon number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8689 + ... + 15444.

It is an arithmetic number, because the mean of its divisors is an integer number (10208682).

Almost surely, 2^81521274 is an apocalyptic number.

81521274 is an abundant number, since it is smaller than the sum of its proper divisors (81817638).

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

81521274 is a wasteful number, since it uses less digits than its factorization.

81521274 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24701.

The product of its digits is 4480, while the sum is 30.

The square root of 81521274 is about 9028.9132236388. The cubic root of 81521274 is about 433.6010441747.

The spelling of 81521274 in words is "eighty-one million, five hundred twenty-one thousand, two hundred seventy-four".