121257077721 has 32 divisors (see below), whose sum is σ = 183324503040. Its totient is φ = 70673891904.

The previous prime is 121257077663. The next prime is 121257077737. The reversal of 121257077721 is 127770752121.

It is a happy number.

It is not a de Polignac number, because 121257077721 - 2¹³ = 121257069529 is a prime.

It is not an unprimeable number, because it can be changed into a prime (121257077761) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3124780 + ... + 3163346.

It is an arithmetic number, because the mean of its divisors is an integer number (5728890720).

Almost surely, 2^121257077721 is an apocalyptic number.

It is an amenable number.

121257077721 is a deficient number, since it is larger than the sum of its proper divisors (62067425319).

121257077721 is a wasteful number, since it uses less digits than its factorization.

121257077721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42845.

The product of its (nonzero) digits is 96040, while the sum is 42.

The spelling of 121257077721 in words is "one hundred twenty-one billion, two hundred fifty-seven million, seventy-seven thousand, seven hundred twenty-one".