56215391 has 2 divisors, whose sum is σ = 56215392. Its totient is φ = 56215390.

The previous prime is 56215363. The next prime is 56215417. The reversal of 56215391 is 19351265.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-56215391 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (56215301) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 28107695 + 28107696.

It is an arithmetic number, because the mean of its divisors is an integer number (28107696).

Almost surely, 2^56215391 is an apocalyptic number.

56215391 is a deficient number, since it is larger than the sum of its proper divisors (1).

56215391 is an equidigital number, since it uses as much as digits as its factorization.

56215391 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 8100, while the sum is 32.

The square root of 56215391 is about 7497.6923783255. The cubic root of 56215391 is about 383.0761187323.

The spelling of 56215391 in words is "fifty-six million, two hundred fifteen thousand, three hundred ninety-one".