55639980 has 384 divisors, whose sum is σ = 217728000. Its totient is φ = 11612160.

The previous prime is 55639939. The next prime is 55639981. The reversal of 55639980 is 8993655.

55639980 is a `hidden beast` number, since 5 + 5 + 639 + 9 + 8 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is not an unprimeable number, because it can be changed into a prime (55639981) by changing a digit.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 1918606 + ... + 1918634.

It is an arithmetic number, because the mean of its divisors is an integer number (567000).

Almost surely, 2^55639980 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 55639980, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (108864000).

55639980 is an abundant number, since it is smaller than the sum of its proper divisors (162088020).

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

55639980 is a wasteful number, since it uses less digits than its factorization.

55639980 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 94 (or 86 counting only the distinct ones).

The product of its (nonzero) digits is 291600, while the sum is 45.

The square root of 55639980 is about 7459.2211389662. The cubic root of 55639980 is about 381.7646000877.

The spelling of 55639980 in words is "fifty-five million, six hundred thirty-nine thousand, nine hundred eighty".