55779840 has 200 divisors, whose sum is σ = 200528460. Its totient is φ = 14819328.

The previous prime is 55779833. The next prime is 55779863. The reversal of 55779840 is 4897755.

55779840 is a `hidden beast` number, since 557 + 7 + 98 + 4 + 0 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 49787136 + 5992704 = 7056^2 + 2448^2 .

It is a super-2 number, since 2×55779840² = 6222781100851200, which contains 22 as substring.

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

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 207226 + ... + 207494.

Almost surely, 2^55779840 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 55779840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (100264230).

55779840 is an abundant number, since it is smaller than the sum of its proper divisors (144748620).

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

55779840 is an equidigital number, since it uses as much as digits as its factorization.

55779840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 304 (or 279 counting only the distinct ones).

The product of its (nonzero) digits is 352800, while the sum is 45.

The square root of 55779840 is about 7468.5902284166. The cubic root of 55779840 is about 382.0842079282.

The spelling of 55779840 in words is "fifty-five million, seven hundred seventy-nine thousand, eight hundred forty".