1631121687 has 12 divisors (see below), whose sum is σ = 2537300584. Its totient is φ = 1003767120.

The previous prime is 1631121643. The next prime is 1631121691. The reversal of 1631121687 is 7861211361.

1631121687 is a `hidden beast` number, since 1 + 631 + 1 + 2 + 16 + 8 + 7 = 666.

It is not a de Polignac number, because 1631121687 - 2¹⁸ = 1630859543 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1631121607) 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, 6970489 + ... + 6970722.

Almost surely, 2^1631121687 is an apocalyptic number.

1631121687 is a deficient number, since it is larger than the sum of its proper divisors (906178897).

1631121687 is a wasteful number, since it uses less digits than its factorization.

1631121687 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13941230 (or 13941227 counting only the distinct ones).

The product of its digits is 12096, while the sum is 36.

The square root of 1631121687 is about 40387.1475472086. The cubic root of 1631121687 is about 1177.1418154058.

The spelling of 1631121687 in words is "one billion, six hundred thirty-one million, one hundred twenty-one thousand, six hundred eighty-seven".