121918205525 has 6 divisors (see below), whose sum is σ = 151178574882. Its totient is φ = 97534564400.

The previous prime is 121918205491. The next prime is 121918205543. The reversal of 121918205525 is 525502819121.

It can be written as a sum of positive squares in 3 ways, for example, as 39715204 + 121878490321 = 6302^2 + 349111^2 .

It is not a de Polignac number, because 121918205525 - 2³⁶ = 53198728789 is a prime.

It is a super-2 number, since 2×121918205525² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 2438364086 + ... + 2438364135.

It is an arithmetic number, because the mean of its divisors is an integer number (25196429147).

Almost surely, 2^121918205525 is an apocalyptic number.

It is an amenable number.

121918205525 is a deficient number, since it is larger than the sum of its proper divisors (29260369357).

121918205525 is an equidigital number, since it uses as much as digits as its factorization.

121918205525 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4876728231 (or 4876728226 counting only the distinct ones).

The product of its (nonzero) digits is 72000, while the sum is 41.

The spelling of 121918205525 in words is "one hundred twenty-one billion, nine hundred eighteen million, two hundred five thousand, five hundred twenty-five".