55091820 has 48 divisors (see below), whose sum is σ = 176295168. Its totient is φ = 12592320.

The previous prime is 55091809. The next prime is 55091843. The reversal of 55091820 is 2819055.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 65166 + ... + 66005.

It is an arithmetic number, because the mean of its divisors is an integer number (3672816).

Almost surely, 2^55091820 is an apocalyptic number.

It is an amenable number.

55091820 is an abundant number, since it is smaller than the sum of its proper divisors (121203348).

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

55091820 is a wasteful number, since it uses less digits than its factorization.

55091820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 131190 (or 131188 counting only the distinct ones).

The product of its (nonzero) digits is 3600, while the sum is 30.

The square root of 55091820 is about 7422.3864086963. The cubic root of 55091820 is about 380.5067569596.

The spelling of 55091820 in words is "fifty-five million, ninety-one thousand, eight hundred twenty".