72731531 has 2 divisors, whose sum is σ = 72731532. Its totient is φ = 72731530.

The previous prime is 72731521. The next prime is 72731537. The reversal of 72731531 is 13513727.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 72731531 - 2⁶ = 72731467 is a prime.

It is a super-2 number, since 2×72731531² = 10579751203207922, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 72731494 and 72731503.

It is not a weakly prime, because it can be changed into another prime (72731537) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 36365765 + 36365766.

It is an arithmetic number, because the mean of its divisors is an integer number (36365766).

Almost surely, 2^72731531 is an apocalyptic number.

72731531 is a deficient number, since it is larger than the sum of its proper divisors (1).

72731531 is an equidigital number, since it uses as much as digits as its factorization.

72731531 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4410, while the sum is 29.

The square root of 72731531 is about 8528.2783139389. The cubic root of 72731531 is about 417.4209510061.

The spelling of 72731531 in words is "seventy-two million, seven hundred thirty-one thousand, five hundred thirty-one".