72191831 has 2 divisors, whose sum is σ = 72191832. Its totient is φ = 72191830.

The previous prime is 72191813. The next prime is 72191837. The reversal of 72191831 is 13819127.

Together with previous prime (72191813) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 72191831 - 2⁶ = 72191767 is a prime.

It is a super-2 number, since 2×72191831² = 10423320926265122, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (72191837) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 36095915 + 36095916.

It is an arithmetic number, because the mean of its divisors is an integer number (36095916).

Almost surely, 2^72191831 is an apocalyptic number.

72191831 is a deficient number, since it is larger than the sum of its proper divisors (1).

72191831 is an equidigital number, since it uses as much as digits as its factorization.

72191831 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3024, while the sum is 32.

The square root of 72191831 is about 8496.5776051302. The cubic root of 72191831 is about 416.3859041541.

The spelling of 72191831 in words is "seventy-two million, one hundred ninety-one thousand, eight hundred thirty-one".