72206731 has 4 divisors (see below), whose sum is σ = 72530752. Its totient is φ = 71882712.

The previous prime is 72206663. The next prime is 72206753. The reversal of 72206731 is 13760227.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 13760227 = 13 ⋅1058479.

It is not a de Polignac number, because 72206731 - 2¹¹ = 72204683 is a prime.

It is a super-2 number, since 2×72206731² = 10427624003412722, which contains 22 as substring.

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 72206731.

It is not an unprimeable number, because it can be changed into a prime (72206831) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 161676 + ... + 162121.

It is an arithmetic number, because the mean of its divisors is an integer number (18132688).

Almost surely, 2^72206731 is an apocalyptic number.

72206731 is a deficient number, since it is larger than the sum of its proper divisors (324021).

72206731 is a wasteful number, since it uses less digits than its factorization.

72206731 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 324020.

The product of its (nonzero) digits is 3528, while the sum is 28.

The square root of 72206731 is about 8497.4543835198. The cubic root of 72206731 is about 416.4145487763.

Adding to 72206731 its reverse (13760227), we get a palindrome (85966958).

The spelling of 72206731 in words is "seventy-two million, two hundred six thousand, seven hundred thirty-one".