55555591 has 8 divisors (see below), whose sum is σ = 68376224. Its totient is φ = 43956000.

The previous prime is 55555579. The next prime is 55555631. The reversal of 55555591 is 19555555.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 55555591 - 2⁵ = 55555559 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55555531) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 305160 + ... + 305341.

It is an arithmetic number, because the mean of its divisors is an integer number (8547028).

Almost surely, 2^55555591 is an apocalyptic number.

55555591 is a deficient number, since it is larger than the sum of its proper divisors (12820633).

55555591 is a wasteful number, since it uses less digits than its factorization.

55555591 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 610521.

The product of its digits is 140625, while the sum is 40.

The square root of 55555591 is about 7453.5623026845. The cubic root of 55555591 is about 381.5714953319.

It can be divided in two parts, 555555 and 91, that multiplied together give a palindrome (50555505).

The spelling of 55555591 in words is "fifty-five million, five hundred fifty-five thousand, five hundred ninety-one".