72131905 has 4 divisors (see below), whose sum is σ = 86558292. Its totient is φ = 57705520.

The previous prime is 72131893. The next prime is 72131921. The reversal of 72131905 is 50913127.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 14311089 + 57820816 = 3783^2 + 7604^2 .

It is not a de Polignac number, because 72131905 - 2⁷ = 72131777 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7213186 + ... + 7213195.

It is an arithmetic number, because the mean of its divisors is an integer number (21639573).

Almost surely, 2^72131905 is an apocalyptic number.

It is an amenable number.

72131905 is a deficient number, since it is larger than the sum of its proper divisors (14426387).

72131905 is a wasteful number, since it uses less digits than its factorization.

72131905 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14426386.

The product of its (nonzero) digits is 1890, while the sum is 28.

The square root of 72131905 is about 8493.0503942930. The cubic root of 72131905 is about 416.2706591243.

The spelling of 72131905 in words is "seventy-two million, one hundred thirty-one thousand, nine hundred five".