55780920 has 256 divisors, whose sum is σ = 208656000. Its totient is φ = 13160448.

The previous prime is 55780889. The next prime is 55780931. The reversal of 55780920 is 2908755.

55780920 is a `hidden beast` number, since 557 + 80 + 9 + 20 = 666.

It is a super-2 number, since 2×55780920² = 6223022072092800, which contains 22 as substring.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 407092 + ... + 407228.

Almost surely, 2^55780920 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 55780920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (104328000).

55780920 is an abundant number, since it is smaller than the sum of its proper divisors (152875080).

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

55780920 is a wasteful number, since it uses less digits than its factorization.

55780920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 199 (or 189 counting only the distinct ones).

The product of its (nonzero) digits is 25200, while the sum is 36.

The square root of 55780920 is about 7468.6625308686. The cubic root of 55780920 is about 382.0866738626.

The spelling of 55780920 in words is "fifty-five million, seven hundred eighty thousand, nine hundred twenty".