231415661 has 2 divisors, whose sum is σ = 231415662. Its totient is φ = 231415660.

The previous prime is 231415643. The next prime is 231415729. The reversal of 231415661 is 166514132.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 161442436 + 69973225 = 12706^2 + 8365^2 .

It is a cyclic number.

It is not a de Polignac number, because 231415661 - 2¹⁰ = 231414637 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (231415601) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 115707830 + 115707831.

It is an arithmetic number, because the mean of its divisors is an integer number (115707831).

Almost surely, 2^231415661 is an apocalyptic number.

It is an amenable number.

231415661 is a deficient number, since it is larger than the sum of its proper divisors (1).

231415661 is an equidigital number, since it uses as much as digits as its factorization.

231415661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4320, while the sum is 29.

The square root of 231415661 is about 15212.3522507205. The cubic root of 231415661 is about 613.9470479221.

Adding to 231415661 its reverse (166514132), we get a palindrome (397929793).

The spelling of 231415661 in words is "two hundred thirty-one million, four hundred fifteen thousand, six hundred sixty-one".