231561905 has 8 divisors (see below), whose sum is σ = 278518632. Its totient is φ = 184819968.

The previous prime is 231561893. The next prime is 231561931. The reversal of 231561905 is 509165132.

It can be written as a sum of positive squares in 4 ways, for example, as 2917264 + 228644641 = 1708^2 + 15121^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 231561905 - 2¹⁰ = 231560881 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 51314 + ... + 55643.

It is an arithmetic number, because the mean of its divisors is an integer number (34814829).

Almost surely, 2^231561905 is an apocalyptic number.

It is an amenable number.

231561905 is a deficient number, since it is larger than the sum of its proper divisors (46956727).

231561905 is a wasteful number, since it uses less digits than its factorization.

231561905 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 107395.

The product of its (nonzero) digits is 8100, while the sum is 32.

The square root of 231561905 is about 15217.1582432463. The cubic root of 231561905 is about 614.0763494061.

The spelling of 231561905 in words is "two hundred thirty-one million, five hundred sixty-one thousand, nine hundred five".