55531891 has 2 divisors, whose sum is σ = 55531892. Its totient is φ = 55531890.

The previous prime is 55531859. The next prime is 55531901. The reversal of 55531891 is 19813555.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 55531891 - 2⁵ = 55531859 is a prime.

It is a super-3 number, since 3×55531891³ (a number of 24 digits) contains 333 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 55531891.

It is not a weakly prime, because it can be changed into another prime (55531831) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 27765945 + 27765946.

It is an arithmetic number, because the mean of its divisors is an integer number (27765946).

Almost surely, 2^55531891 is an apocalyptic number.

55531891 is a deficient number, since it is larger than the sum of its proper divisors (1).

55531891 is an equidigital number, since it uses as much as digits as its factorization.

55531891 is an evil number, because the sum of its binary digits is even.

The product of its digits is 27000, while the sum is 37.

The square root of 55531891 is about 7451.9722892668. The cubic root of 55531891 is about 381.5172281824.

The spelling of 55531891 in words is "fifty-five million, five hundred thirty-one thousand, eight hundred ninety-one".