55640857 has 2 divisors, whose sum is σ = 55640858. Its totient is φ = 55640856.

The previous prime is 55640801. The next prime is 55640863. The reversal of 55640857 is 75804655.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 50424201 + 5216656 = 7101^2 + 2284^2 .

It is a cyclic number.

It is not a de Polignac number, because 55640857 - 2⁷ = 55640729 is a prime.

It is not a weakly prime, because it can be changed into another prime (55643857) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 27820428 + 27820429.

It is an arithmetic number, because the mean of its divisors is an integer number (27820429).

Almost surely, 2^55640857 is an apocalyptic number.

It is an amenable number.

55640857 is a deficient number, since it is larger than the sum of its proper divisors (1).

55640857 is an equidigital number, since it uses as much as digits as its factorization.

55640857 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 168000, while the sum is 40.

The square root of 55640857 is about 7459.2799250330. The cubic root of 55640857 is about 381.7666058744.

The spelling of 55640857 in words is "fifty-five million, six hundred forty thousand, eight hundred fifty-seven".