57081391 has 2 divisors, whose sum is σ = 57081392. Its totient is φ = 57081390.

The previous prime is 57081361. The next prime is 57081403. The reversal of 57081391 is 19318075.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 57081391 - 2¹¹ = 57079343 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (57081361) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 28540695 + 28540696.

It is an arithmetic number, because the mean of its divisors is an integer number (28540696).

Almost surely, 2^57081391 is an apocalyptic number.

57081391 is a deficient number, since it is larger than the sum of its proper divisors (1).

57081391 is an equidigital number, since it uses as much as digits as its factorization.

57081391 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 7560, while the sum is 34.

The square root of 57081391 is about 7555.2227630957. Note that the first 3 decimals coincide. The cubic root of 57081391 is about 385.0332034106.

The spelling of 57081391 in words is "fifty-seven million, eighty-one thousand, three hundred ninety-one".