121655543800 has 72 divisors (see below), whose sum is σ = 329028617160. Its totient is φ = 41710468800.

The previous prime is 121655543767. The next prime is 121655543813. The reversal of 121655543800 is 8345556121.

It is a Harshad number since it is a multiple of its sum of digits (40).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 6197116 + ... + 6216715.

It is an arithmetic number, because the mean of its divisors is an integer number (4569841905).

Almost surely, 2^121655543800 is an apocalyptic number.

121655543800 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

121655543800 is an abundant number, since it is smaller than the sum of its proper divisors (207373073360).

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

121655543800 is a wasteful number, since it uses less digits than its factorization.

121655543800 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12413861 (or 12413845 counting only the distinct ones).

The product of its (nonzero) digits is 144000, while the sum is 40.

The spelling of 121655543800 in words is "one hundred twenty-one billion, six hundred fifty-five million, five hundred forty-three thousand, eight hundred".