81272392 has 8 divisors (see below), whose sum is σ = 152385750. Its totient is φ = 40636192.

The previous prime is 81272371. The next prime is 81272419. The reversal of 81272392 is 29327218.

It can be written as a sum of positive squares in only one way, i.e., 74891716 + 6380676 = 8654^2 + 2526^2 .

It is a tau number, because it is divible by the number of its divisors (8).

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 as a sum of consecutive naturals, namely, 5079517 + ... + 5079532.

Almost surely, 2^81272392 is an apocalyptic number.

It is an amenable number.

81272392 is a deficient number, since it is larger than the sum of its proper divisors (71113358).

81272392 is a wasteful number, since it uses less digits than its factorization.

81272392 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10159055 (or 10159051 counting only the distinct ones).

The product of its digits is 12096, while the sum is 34.

The square root of 81272392 is about 9015.1201877734. The cubic root of 81272392 is about 433.1593373770.

The spelling of 81272392 in words is "eighty-one million, two hundred seventy-two thousand, three hundred ninety-two".