81139372 has 12 divisors (see below), whose sum is σ = 145831840. Its totient is φ = 39473136.

The previous prime is 81139363. The next prime is 81139391. The reversal of 81139372 is 27393118.

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 3 ways as a sum of consecutive naturals, for example, 273972 + ... + 274267.

Almost surely, 2^81139372 is an apocalyptic number.

It is an amenable number.

81139372 is a deficient number, since it is larger than the sum of its proper divisors (64692468).

81139372 is a wasteful number, since it uses less digits than its factorization.

81139372 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 548280 (or 548278 counting only the distinct ones).

The product of its digits is 9072, while the sum is 34.

The square root of 81139372 is about 9007.7395610664. The cubic root of 81139372 is about 432.9228884119.

The spelling of 81139372 in words is "eighty-one million, one hundred thirty-nine thousand, three hundred seventy-two".