72642697621 has 4 divisors (see below), whose sum is σ = 78230597452. Its totient is φ = 67054797792.

The previous prime is 72642697601. The next prime is 72642697669. The reversal of 72642697621 is 12679624627.

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 14711021521 + 57931676100 = 121289^2 + 240690^2 .

It is a cyclic number.

It is not a de Polignac number, because 72642697621 - 2²⁷ = 72508479893 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 (72642697601) 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, 2793949896 + ... + 2793949921.

It is an arithmetic number, because the mean of its divisors is an integer number (19557649363).

Almost surely, 2^72642697621 is an apocalyptic number.

It is an amenable number.

72642697621 is a deficient number, since it is larger than the sum of its proper divisors (5587899831).

72642697621 is a wasteful number, since it uses less digits than its factorization.

72642697621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5587899830.

The product of its digits is 3048192, while the sum is 52.

The spelling of 72642697621 in words is "seventy-two billion, six hundred forty-two million, six hundred ninety-seven thousand, six hundred twenty-one".