121515615515 has 16 divisors (see below), whose sum is σ = 172025794560. Its totient is φ = 80637089760.

The previous prime is 121515615493. The next prime is 121515615523. The reversal of 121515615515 is 515516515121.

It is not a de Polignac number, because 121515615515 - 2²⁰ = 121514566939 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 55996895 + ... + 55999064.

It is an arithmetic number, because the mean of its divisors is an integer number (10751612160).

Almost surely, 2^121515615515 is an apocalyptic number.

121515615515 is a deficient number, since it is larger than the sum of its proper divisors (50510179045).

121515615515 is a wasteful number, since it uses less digits than its factorization.

121515615515 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 111996002.

The product of its digits is 37500, while the sum is 38.

The spelling of 121515615515 in words is "one hundred twenty-one billion, five hundred fifteen million, six hundred fifteen thousand, five hundred fifteen".