72131405 has 8 divisors (see below), whose sum is σ = 86969184. Its totient is φ = 57430800.

The previous prime is 72131393. The next prime is 72131407. The reversal of 72131405 is 50413127.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 72131405 - 2¹⁸ = 71869261 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (72131407) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 33131 + ... + 35240.

It is an arithmetic number, because the mean of its divisors is an integer number (10871148).

Almost surely, 2^72131405 is an apocalyptic number.

It is an amenable number.

72131405 is a deficient number, since it is larger than the sum of its proper divisors (14837779).

72131405 is a wasteful number, since it uses less digits than its factorization.

72131405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 68587.

The product of its (nonzero) digits is 840, while the sum is 23.

The square root of 72131405 is about 8493.0209584105. The cubic root of 72131405 is about 416.2696972946.

The spelling of 72131405 in words is "seventy-two million, one hundred thirty-one thousand, four hundred five".