72639137 has 4 divisors (see below), whose sum is σ = 72826260. Its totient is φ = 72452016.

The previous prime is 72639131. The next prime is 72639143. The reversal of 72639137 is 73193627.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 73193627 = 13 ⋅5630279.

It is an interprime number because it is at equal distance from previous prime (72639131) and next prime (72639143).

It can be written as a sum of positive squares in 2 ways, for example, as 38987536 + 33651601 = 6244^2 + 5801^2 .

It is a cyclic number.

It is not a de Polignac number, because 72639137 - 2²⁴ = 55861921 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 72639137.

It is not an unprimeable number, because it can be changed into a prime (72639131) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 92978 + ... + 93755.

It is an arithmetic number, because the mean of its divisors is an integer number (18206565).

Almost surely, 2^72639137 is an apocalyptic number.

It is an amenable number.

72639137 is a deficient number, since it is larger than the sum of its proper divisors (187123).

72639137 is a wasteful number, since it uses less digits than its factorization.

72639137 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 187122.

The product of its digits is 47628, while the sum is 38.

The square root of 72639137 is about 8522.8596726686. The cubic root of 72639137 is about 417.2441201620.

The spelling of 72639137 in words is "seventy-two million, six hundred thirty-nine thousand, one hundred thirty-seven".