1231998648777 has 18 divisors (see below), whose sum is σ = 1926972247902. Its totient is φ = 758153013696.

The previous prime is 1231998648763. The next prime is 1231998648809. The reversal of 1231998648777 is 7778468991321.

1231998648777 is a `hidden beast` number, since 123 + 19 + 9 + 8 + 6 + 487 + 7 + 7 = 666.

It can be written as a sum of positive squares in 3 ways, for example, as 121976261001 + 1110022387776 = 349251^2 + 1053576^2 .

It is not a de Polignac number, because 1231998648777 - 2²² = 1231994454473 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1231998648277) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 404994748 + ... + 404997789.

Almost surely, 2^{1231998648777} is an apocalyptic number.

It is an amenable number.

1231998648777 is a deficient number, since it is larger than the sum of its proper divisors (694973599125).

1231998648777 is a wasteful number, since it uses less digits than its factorization.

1231998648777 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 809992569 (or 809992553 counting only the distinct ones).

The product of its digits is 256048128, while the sum is 72.

The spelling of 1231998648777 in words is "one trillion, two hundred thirty-one billion, nine hundred ninety-eight million, six hundred forty-eight thousand, seven hundred seventy-seven".