121815864 has 48 divisors (see below), whose sum is σ = 340566720. Its totient is φ = 39294720.

The previous prime is 121815853. The next prime is 121815899. The reversal of 121815864 is 468518121.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 25057 + ... + 29520.

It is an arithmetic number, because the mean of its divisors is an integer number (7095140).

Almost surely, 2^121815864 is an apocalyptic number.

It is an amenable number.

121815864 is an abundant number, since it is smaller than the sum of its proper divisors (218750856).

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

121815864 is a wasteful number, since it uses less digits than its factorization.

121815864 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 54620 (or 54613 counting only the distinct ones).

The product of its digits is 15360, while the sum is 36.

The square root of 121815864 is about 11037.0224245491. The cubic root of 121815864 is about 495.7179175630.

The spelling of 121815864 in words is "one hundred twenty-one million, eight hundred fifteen thousand, eight hundred sixty-four".