55521660 has 96 divisors (see below), whose sum is σ = 170372160. Its totient is φ = 13447168.

The previous prime is 55521659. The next prime is 55521673. The reversal of 55521660 is 6612555.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 28642 + ... + 30518.

It is an arithmetic number, because the mean of its divisors is an integer number (1774710).

Almost surely, 2^55521660 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 55521660, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (85186080).

55521660 is an abundant number, since it is smaller than the sum of its proper divisors (114850500).

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

55521660 is a wasteful number, since it uses less digits than its factorization.

55521660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1935 (or 1933 counting only the distinct ones).

The product of its (nonzero) digits is 9000, while the sum is 30.

The square root of 55521660 is about 7451.2857950826. The cubic root of 55521660 is about 381.4937969466.

The spelling of 55521660 in words is "fifty-five million, five hundred twenty-one thousand, six hundred sixty".