55017978 has 16 divisors (see below), whose sum is σ = 114820416. Its totient is φ = 17541920.

The previous prime is 55017973. The next prime is 55018013. The reversal of 55017978 is 87971055.

It is not an unprimeable number, because it can be changed into a prime (55017973) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 199203 + ... + 199478.

It is an arithmetic number, because the mean of its divisors is an integer number (7176276).

Almost surely, 2^55017978 is an apocalyptic number.

55017978 is an abundant number, since it is smaller than the sum of its proper divisors (59802438).

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

55017978 is a wasteful number, since it uses less digits than its factorization.

55017978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 398709.

The product of its (nonzero) digits is 88200, while the sum is 42.

The square root of 55017978 is about 7417.4104645759. The cubic root of 55017978 is about 380.3366776103.

It can be divided in two parts, 550 and 17978, that added together give a triangular number (18528 = T₁₉₂).

The spelling of 55017978 in words is "fifty-five million, seventeen thousand, nine hundred seventy-eight".