121861665636 has 24 divisors (see below), whose sum is σ = 284355788640. Its totient is φ = 40618854912.

The previous prime is 121861665617. The next prime is 121861665643. The reversal of 121861665636 is 636566168121.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 105075 + ... + 504741.

It is an arithmetic number, because the mean of its divisors is an integer number (11848157860).

Almost surely, 2^121861665636 is an apocalyptic number.

It is an amenable number.

121861665636 is an abundant number, since it is smaller than the sum of its proper divisors (162494123004).

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

121861665636 is a wasteful number, since it uses less digits than its factorization.

121861665636 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 425083 (or 425081 counting only the distinct ones).

The product of its digits is 1866240, while the sum is 51.

The spelling of 121861665636 in words is "one hundred twenty-one billion, eight hundred sixty-one million, six hundred sixty-five thousand, six hundred thirty-six".