72640731 has 8 divisors (see below), whose sum is σ = 99472144. Its totient is φ = 47118240.

The previous prime is 72640703. The next prime is 72640747. The reversal of 72640731 is 13704627.

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

It is not a de Polignac number, because 72640731 - 2⁹ = 72640219 is a prime.

It is a super-2 number, since 2×72640731² = 10553351600428722, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (72640531) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 327100 + ... + 327321.

It is an arithmetic number, because the mean of its divisors is an integer number (12434018).

Almost surely, 2^72640731 is an apocalyptic number.

72640731 is a deficient number, since it is larger than the sum of its proper divisors (26831413).

72640731 is a wasteful number, since it uses less digits than its factorization.

72640731 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 654461.

The product of its (nonzero) digits is 7056, while the sum is 30.

The square root of 72640731 is about 8522.9531853695. The cubic root of 72640731 is about 417.2471721543.

The spelling of 72640731 in words is "seventy-two million, six hundred forty thousand, seven hundred thirty-one".