55785978 has 24 divisors (see below), whose sum is σ = 122574816. Its totient is φ = 18333000.

The previous prime is 55785941. The next prime is 55785979. The reversal of 55785978 is 87958755.

55785978 is a `hidden beast` number, since 557 + 85 + 9 + 7 + 8 = 666.

It is a super-2 number, since 2×55785978² = 6224150682832968, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (55785979) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 20548 + ... + 23103.

It is an arithmetic number, because the mean of its divisors is an integer number (5107284).

Almost surely, 2^55785978 is an apocalyptic number.

55785978 is an abundant number, since it is smaller than the sum of its proper divisors (66788838).

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

55785978 is a wasteful number, since it uses less digits than its factorization.

55785978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43730 (or 43727 counting only the distinct ones).

The product of its digits is 3528000, while the sum is 54.

The square root of 55785978 is about 7469.0011380371. The cubic root of 55785978 is about 382.0982222319.

The spelling of 55785978 in words is "fifty-five million, seven hundred eighty-five thousand, nine hundred seventy-eight".