55591931 has 2 divisors, whose sum is σ = 55591932. Its totient is φ = 55591930.

The previous prime is 55591919. The next prime is 55591933. The reversal of 55591931 is 13919555.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 55591931 - 2¹⁰ = 55590907 is a prime.

It is a super-2 number, since 2×55591931² = 6180925584617522, which contains 22 as substring.

Together with 55591933, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (55591933) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 27795965 + 27795966.

It is an arithmetic number, because the mean of its divisors is an integer number (27795966).

Almost surely, 2^55591931 is an apocalyptic number.

55591931 is a deficient number, since it is larger than the sum of its proper divisors (1).

55591931 is an equidigital number, since it uses as much as digits as its factorization.

55591931 is an evil number, because the sum of its binary digits is even.

The product of its digits is 30375, while the sum is 38.

The square root of 55591931 is about 7455.9996646996. Note that the first 3 decimals coincide. The cubic root of 55591931 is about 381.6546749939.

The spelling of 55591931 in words is "fifty-five million, five hundred ninety-one thousand, nine hundred thirty-one".