72639751 has 4 divisors (see below), whose sum is σ = 75144600. Its totient is φ = 70134904.

The previous prime is 72639731. The next prime is 72639757. The reversal of 72639751 is 15793627.

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

It is a cyclic number.

It is not a de Polignac number, because 72639751 - 2⁵ = 72639719 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (72639757) by changing a digit.

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 in 3 ways as a sum of consecutive naturals, for example, 1252381 + ... + 1252438.

It is an arithmetic number, because the mean of its divisors is an integer number (18786150).

Almost surely, 2^72639751 is an apocalyptic number.

72639751 is a deficient number, since it is larger than the sum of its proper divisors (2504849).

72639751 is a wasteful number, since it uses less digits than its factorization.

72639751 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2504848.

The product of its digits is 79380, while the sum is 40.

The square root of 72639751 is about 8522.8956933662. The cubic root of 72639751 is about 417.2452957779.

The spelling of 72639751 in words is "seventy-two million, six hundred thirty-nine thousand, seven hundred fifty-one".