72167731 has 2 divisors, whose sum is σ = 72167732. Its totient is φ = 72167730.

The previous prime is 72167729. The next prime is 72167741. The reversal of 72167731 is 13776127.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 72167731 - 2¹ = 72167729 is a prime.

It is a super-2 number, since 2×72167731² = 10416362795376722, which contains 22 as substring.

Together with 72167729, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (72167741) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 36083865 + 36083866.

It is an arithmetic number, because the mean of its divisors is an integer number (36083866).

Almost surely, 2^72167731 is an apocalyptic number.

72167731 is a deficient number, since it is larger than the sum of its proper divisors (1).

72167731 is an equidigital number, since it uses as much as digits as its factorization.

72167731 is an evil number, because the sum of its binary digits is even.

The product of its digits is 12348, while the sum is 34.

The square root of 72167731 is about 8495.1592686659. The cubic root of 72167731 is about 416.3395645751.

The spelling of 72167731 in words is "seventy-two million, one hundred sixty-seven thousand, seven hundred thirty-one".