121100511978 has 24 divisors (see below), whose sum is σ = 264931868448. Its totient is φ = 39974925672.

The previous prime is 121100511971. The next prime is 121100511989. The reversal of 121100511978 is 879115001121.

121100511978 is a `hidden beast` number, since 121 + 10 + 0 + 511 + 9 + 7 + 8 = 666.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (121100511971) 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, 32657400 + ... + 32661107.

It is an arithmetic number, because the mean of its divisors is an integer number (11038827852).

Almost surely, 2^121100511978 is an apocalyptic number.

121100511978 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

121100511978 is an abundant number, since it is smaller than the sum of its proper divisors (143831356470).

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

121100511978 is a wasteful number, since it uses less digits than its factorization.

121100511978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 65318618 (or 65318615 counting only the distinct ones).

The product of its (nonzero) digits is 5040, while the sum is 36.

The spelling of 121100511978 in words is "one hundred twenty-one billion, one hundred million, five hundred eleven thousand, nine hundred seventy-eight".