55778220 has 144 divisors (see below), whose sum is σ = 183456000. Its totient is φ = 14198976.

The previous prime is 55778119. The next prime is 55778231. The reversal of 55778220 is 2287755.

55778220 is a `hidden beast` number, since 5 + 577 + 82 + 2 + 0 = 666.

It is a super-2 number, since 2×55778220² = 6222419652736800, which contains 22 as substring.

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

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 111531 + ... + 112029.

It is an arithmetic number, because the mean of its divisors is an integer number (1274000).

Almost surely, 2^55778220 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 55778220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (91728000).

55778220 is an abundant number, since it is smaller than the sum of its proper divisors (127677780).

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

55778220 is a wasteful number, since it uses less digits than its factorization.

55778220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 546 (or 532 counting only the distinct ones).

The product of its (nonzero) digits is 39200, while the sum is 36.

The square root of 55778220 is about 7468.4817734262. The cubic root of 55778220 is about 382.0805089669.

The spelling of 55778220 in words is "fifty-five million, seven hundred seventy-eight thousand, two hundred twenty".