72561631 has 4 divisors (see below), whose sum is σ = 72937792. Its totient is φ = 72185472.

The previous prime is 72561613. The next prime is 72561641. The reversal of 72561631 is 13616527.

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 72561631 - 2⁹ = 72561119 is a prime.

It is a super-2 number, since 2×72561631² = 10530380586760322, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 72561593 and 72561602.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (72561641) 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, 187791 + ... + 188176.

It is an arithmetic number, because the mean of its divisors is an integer number (18234448).

Almost surely, 2^72561631 is an apocalyptic number.

72561631 is a deficient number, since it is larger than the sum of its proper divisors (376161).

72561631 is a wasteful number, since it uses less digits than its factorization.

72561631 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 376160.

The product of its digits is 7560, while the sum is 31.

The square root of 72561631 is about 8518.3115110919. The cubic root of 72561631 is about 417.0956674462.

The spelling of 72561631 in words is "seventy-two million, five hundred sixty-one thousand, six hundred thirty-one".