55181920 has 24 divisors (see below), whose sum is σ = 130367664. Its totient is φ = 22072704.

The previous prime is 55181897. The next prime is 55181921. The reversal of 55181920 is 2918155.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55181921) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 172284 + ... + 172603.

It is an arithmetic number, because the mean of its divisors is an integer number (5431986).

Almost surely, 2^55181920 is an apocalyptic number.

It is an amenable number.

55181920 is an abundant number, since it is smaller than the sum of its proper divisors (75185744).

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

55181920 is a wasteful number, since it uses less digits than its factorization.

55181920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 344902 (or 344894 counting only the distinct ones).

The product of its (nonzero) digits is 3600, while the sum is 31.

The square root of 55181920 is about 7428.4534056559. The cubic root of 55181920 is about 380.7140774293.

The spelling of 55181920 in words is "fifty-five million, one hundred eighty-one thousand, nine hundred twenty".