55991663 has 32 divisors (see below), whose sum is σ = 72912000. Its totient is φ = 42674688.

The previous prime is 55991603. The next prime is 55991669. The reversal of 55991663 is 36619955.

It is not a de Polignac number, because 55991663 - 2⁶ = 55991599 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55991669) 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 in 31 ways as a sum of consecutive naturals, for example, 129095 + ... + 129527.

It is an arithmetic number, because the mean of its divisors is an integer number (2278500).

Almost surely, 2^55991663 is an apocalyptic number.

55991663 is a deficient number, since it is larger than the sum of its proper divisors (16920337).

55991663 is a wasteful number, since it uses less digits than its factorization.

55991663 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 496 (or 482 counting only the distinct ones).

The product of its digits is 218700, while the sum is 44.

The square root of 55991663 is about 7482.7577135706. The cubic root of 55991663 is about 382.5672497702.

The spelling of 55991663 in words is "fifty-five million, nine hundred ninety-one thousand, six hundred sixty-three".