231561639487 has 32 divisors (see below), whose sum is σ = 257901926400. Its totient is φ = 206790904320.

The previous prime is 231561639481. The next prime is 231561639503. The reversal of 231561639487 is 784936165132.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 231561639487 - 2⁷ = 231561639359 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (231561639481) 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, 53071768 + ... + 53076130.

It is an arithmetic number, because the mean of its divisors is an integer number (8059435200).

Almost surely, 2^231561639487 is an apocalyptic number.

231561639487 is a deficient number, since it is larger than the sum of its proper divisors (26340286913).

231561639487 is a wasteful number, since it uses less digits than its factorization.

231561639487 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5463.

The product of its digits is 6531840, while the sum is 55.

The spelling of 231561639487 in words is "two hundred thirty-one billion, five hundred sixty-one million, six hundred thirty-nine thousand, four hundred eighty-seven".