55991599 has 2 divisors, whose sum is σ = 55991600. Its totient is φ = 55991598.

The previous prime is 55991587. The next prime is 55991603. The reversal of 55991599 is 99519955.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 55991599 - 2⁵ = 55991567 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (55991519) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 27995799 + 27995800.

It is an arithmetic number, because the mean of its divisors is an integer number (27995800).

Almost surely, 2^55991599 is an apocalyptic number.

55991599 is a deficient number, since it is larger than the sum of its proper divisors (1).

55991599 is an equidigital number, since it uses as much as digits as its factorization.

55991599 is an evil number, because the sum of its binary digits is even.

The product of its digits is 820125, while the sum is 52.

The square root of 55991599 is about 7482.7534370711. The cubic root of 55991599 is about 382.5671040086.

The spelling of 55991599 in words is "fifty-five million, nine hundred ninety-one thousand, five hundred ninety-nine".