81572416 has 28 divisors (see below), whose sum is σ = 163700460. Its totient is φ = 40325120.

The previous prime is 81572399. The next prime is 81572429. The reversal of 81572416 is 61427518.

It can be written as a sum of positive squares in 2 ways, for example, as 6230016 + 75342400 = 2496^2 + 8680^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1465 + ... + 12856.

It is an arithmetic number, because the mean of its divisors is an integer number (5846445).

Almost surely, 2^81572416 is an apocalyptic number.

It is an amenable number.

81572416 is an abundant number, since it is smaller than the sum of its proper divisors (82128044).

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

81572416 is a wasteful number, since it uses less digits than its factorization.

81572416 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14422 (or 14412 counting only the distinct ones).

The product of its digits is 13440, while the sum is 34.

The square root of 81572416 is about 9031.7449033949. The cubic root of 81572416 is about 433.6916977671.

The spelling of 81572416 in words is "eighty-one million, five hundred seventy-two thousand, four hundred sixteen".