55905990 has 64 divisors (see below), whose sum is σ = 156266496. Its totient is φ = 12534912.

The previous prime is 55905947. The next prime is 55906021. The reversal of 55905990 is 9950955.

55905990 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 8619 + ... + 13641.

It is an arithmetic number, because the mean of its divisors is an integer number (2441664).

Almost surely, 2^55905990 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 55905990, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (78133248).

55905990 is an abundant number, since it is smaller than the sum of its proper divisors (100360506).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

55905990 is a wasteful number, since it uses less digits than its factorization.

55905990 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5093.

The product of its (nonzero) digits is 91125, while the sum is 42.

The square root of 55905990 is about 7477.0308278086. The cubic root of 55905990 is about 382.3720277605.

The spelling of 55905990 in words is "fifty-five million, nine hundred five thousand, nine hundred ninety".