55919581 has 2 divisors, whose sum is σ = 55919582. Its totient is φ = 55919580.

The previous prime is 55919573. The next prime is 55919587. The reversal of 55919581 is 18591955.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 48580900 + 7338681 = 6970^2 + 2709^2 .

It is a cyclic number.

It is not a de Polignac number, because 55919581 - 2³ = 55919573 is a prime.

It is a super-2 number, since 2×55919581² = 6253999078431122, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (55919587) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 27959790 + 27959791.

It is an arithmetic number, because the mean of its divisors is an integer number (27959791).

Almost surely, 2^55919581 is an apocalyptic number.

It is an amenable number.

55919581 is a deficient number, since it is larger than the sum of its proper divisors (1).

55919581 is an equidigital number, since it uses as much as digits as its factorization.

55919581 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 81000, while the sum is 43.

The square root of 55919581 is about 7477.9396226501. The cubic root of 55919581 is about 382.4030107086.

The spelling of 55919581 in words is "fifty-five million, nine hundred nineteen thousand, five hundred eighty-one".