121878916331521 has 4 divisors (see below), whose sum is σ = 121892322887344. Its totient is φ = 121865509775700.

The previous prime is 121878916331429. The next prime is 121878916331539. The reversal of 121878916331521 is 125133619878121.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 121878916331521 - 2⁹ = 121878916331009 is a prime.

It is a super-2 number, since 2×121878916331521² (a number of 29 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (121878916331581) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6703264275 + ... + 6703282456.

It is an arithmetic number, because the mean of its divisors is an integer number (30473080721836).

Almost surely, 2^{121878916331521} is an apocalyptic number.

It is an amenable number.

121878916331521 is a deficient number, since it is larger than the sum of its proper divisors (13406555823).

121878916331521 is an equidigital number, since it uses as much as digits as its factorization.

121878916331521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13406555822.

The product of its digits is 4354560, while the sum is 58.

The spelling of 121878916331521 in words is "one hundred twenty-one trillion, eight hundred seventy-eight billion, nine hundred sixteen million, three hundred thirty-one thousand, five hundred twenty-one".