121645636505 has 16 divisors (see below), whose sum is σ = 148177978560. Its totient is φ = 95848180032.

The previous prime is 121645636471. The next prime is 121645636507. The reversal of 121645636505 is 505636546121.

It is a cyclic number.

It is not a de Polignac number, because 121645636505 - 2²⁶ = 121578527641 is a prime.

It is not an unprimeable number, because it can be changed into a prime (121645636507) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2260451 + ... + 2313639.

It is an arithmetic number, because the mean of its divisors is an integer number (9261123660).

Almost surely, 2^121645636505 is an apocalyptic number.

It is an amenable number.

121645636505 is a deficient number, since it is larger than the sum of its proper divisors (26532342055).

121645636505 is an equidigital number, since it uses as much as digits as its factorization.

121645636505 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 60088.

The product of its (nonzero) digits is 648000, while the sum is 44.

The spelling of 121645636505 in words is "one hundred twenty-one billion, six hundred forty-five million, six hundred thirty-six thousand, five hundred five".