55666017978 has 32 divisors (see below), whose sum is σ = 114602112576. Its totient is φ = 18017545728.

The previous prime is 55666017949. The next prime is 55666017997. The reversal of 55666017978 is 87971066655.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 871476 + ... + 933167.

It is an arithmetic number, because the mean of its divisors is an integer number (3581316018).

Almost surely, 2^55666017978 is an apocalyptic number.

55666017978 is an abundant number, since it is smaller than the sum of its proper divisors (58936094598).

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

55666017978 is a wasteful number, since it uses less digits than its factorization.

55666017978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1804798.

The product of its (nonzero) digits is 19051200, while the sum is 60.

The spelling of 55666017978 in words is "fifty-five billion, six hundred sixty-six million, seventeen thousand, nine hundred seventy-eight".