231540997 has 2 divisors, whose sum is σ = 231540998. Its totient is φ = 231540996.

The previous prime is 231540937. The next prime is 231541007. The reversal of 231540997 is 799045132.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 231070401 + 470596 = 15201^2 + 686^2 .

It is a cyclic number.

It is not a de Polignac number, because 231540997 - 2²⁷ = 97323269 is a prime.

It is a super-2 number, since 2×231540997² = 107222466583508018, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (231540937) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 115770498 + 115770499.

It is an arithmetic number, because the mean of its divisors is an integer number (115770499).

Almost surely, 2^231540997 is an apocalyptic number.

It is an amenable number.

231540997 is a deficient number, since it is larger than the sum of its proper divisors (1).

231540997 is an equidigital number, since it uses as much as digits as its factorization.

231540997 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 68040, while the sum is 40.

The square root of 231540997 is about 15216.4712400740. The cubic root of 231540997 is about 614.0578669550.

The spelling of 231540997 in words is "two hundred thirty-one million, five hundred forty thousand, nine hundred ninety-seven".