121815801 has 12 divisors (see below), whose sum is σ = 177771412. Its totient is φ = 80372736.

The previous prime is 121815791. The next prime is 121815817. The reversal of 121815801 is 108518121.

121815801 is a `hidden beast` number, since 1 + 2 + 1 + 81 + 580 + 1 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 73874025 + 47941776 = 8595^2 + 6924^2 .

It is not a de Polignac number, because 121815801 - 2⁵ = 121815769 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (121815851) 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, 68896 + ... + 70641.

Almost surely, 2^121815801 is an apocalyptic number.

It is an amenable number.

121815801 is a deficient number, since it is larger than the sum of its proper divisors (55955611).

121815801 is a wasteful number, since it uses less digits than its factorization.

121815801 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 139640 (or 139637 counting only the distinct ones).

The product of its (nonzero) digits is 640, while the sum is 27.

The square root of 121815801 is about 11037.0195705181. The cubic root of 121815801 is about 495.7178321055.

The spelling of 121815801 in words is "one hundred twenty-one million, eight hundred fifteen thousand, eight hundred one".