661123085121 has 12 divisors (see below), whose sum is σ = 971141255760. Its totient is φ = 433278405720.

The previous prime is 661123085099. The next prime is 661123085201. The reversal of 661123085121 is 121580321166.

661123085121 is a `hidden beast` number, since 6 + 611 + 2 + 30 + 8 + 5 + 1 + 2 + 1 = 666.

It is not a de Polignac number, because 661123085121 - 2¹¹ = 661123083073 is a prime.

It is not an unprimeable number, because it can be changed into a prime (661123085521) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 622525915 + ... + 622526976.

It is an arithmetic number, because the mean of its divisors is an integer number (80928437980).

Almost surely, 2^661123085121 is an apocalyptic number.

It is an amenable number.

661123085121 is a deficient number, since it is larger than the sum of its proper divisors (310018170639).

661123085121 is a wasteful number, since it uses less digits than its factorization.

661123085121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1245052956 (or 1245052953 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 36.

The spelling of 661123085121 in words is "six hundred sixty-one billion, one hundred twenty-three million, eighty-five thousand, one hundred twenty-one".