55621816 has 16 divisors (see below), whose sum is σ = 109780200. Its totient is φ = 26347104.

The previous prime is 55621801. The next prime is 55621817. The reversal of 55621816 is 61812655.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55621817) 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, 182815 + ... + 183118.

Almost surely, 2^55621816 is an apocalyptic number.

It is an amenable number.

55621816 is a deficient number, since it is larger than the sum of its proper divisors (54158384).

55621816 is a wasteful number, since it uses less digits than its factorization.

55621816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 365958 (or 365954 counting only the distinct ones).

The product of its digits is 14400, while the sum is 34.

The square root of 55621816 is about 7458.0034861885. The cubic root of 55621816 is about 381.7230524636.

The spelling of 55621816 in words is "fifty-five million, six hundred twenty-one thousand, eight hundred sixteen".