72156391 has 2 divisors, whose sum is σ = 72156392. Its totient is φ = 72156390.

The previous prime is 72156389. The next prime is 72156439. The reversal of 72156391 is 19365127.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 72156391 - 2¹ = 72156389 is a prime.

Together with 72156389, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (72156311) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 36078195 + 36078196.

It is an arithmetic number, because the mean of its divisors is an integer number (36078196).

Almost surely, 2^72156391 is an apocalyptic number.

72156391 is a deficient number, since it is larger than the sum of its proper divisors (1).

72156391 is an equidigital number, since it uses as much as digits as its factorization.

72156391 is an evil number, because the sum of its binary digits is even.

The product of its digits is 11340, while the sum is 34.

The square root of 72156391 is about 8494.4918035160. The cubic root of 72156391 is about 416.3177564072.

The spelling of 72156391 in words is "seventy-two million, one hundred fifty-six thousand, three hundred ninety-one".