81539952 has 80 divisors (see below), whose sum is σ = 228631200. Its totient is φ = 24892416.

The previous prime is 81539933. The next prime is 81539977. The reversal of 81539952 is 25993518.

It is a congruent number.

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 15 ways as a sum of consecutive naturals, for example, 92538 + ... + 93414.

It is an arithmetic number, because the mean of its divisors is an integer number (2857890).

Almost surely, 2^81539952 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81539952, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (114315600).

81539952 is an abundant number, since it is smaller than the sum of its proper divisors (147091248).

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

81539952 is a wasteful number, since it uses less digits than its factorization.

81539952 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1050 (or 1044 counting only the distinct ones).

The product of its digits is 97200, while the sum is 42.

The square root of 81539952 is about 9029.9475081531. The cubic root of 81539952 is about 433.6341569294.

The spelling of 81539952 in words is "eighty-one million, five hundred thirty-nine thousand, nine hundred fifty-two".