231151561 has 2 divisors, whose sum is σ = 231151562. Its totient is φ = 231151560.

The previous prime is 231151559. The next prime is 231151589. The reversal of 231151561 is 165151132.

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., 218477961 + 12673600 = 14781^2 + 3560^2 .

It is a cyclic number.

It is not a de Polignac number, because 231151561 - 2¹ = 231151559 is a prime.

Together with 231151559, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (231151861) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 115575780 + 115575781.

It is an arithmetic number, because the mean of its divisors is an integer number (115575781).

Almost surely, 2^231151561 is an apocalyptic number.

It is an amenable number.

231151561 is a deficient number, since it is larger than the sum of its proper divisors (1).

231151561 is an equidigital number, since it uses as much as digits as its factorization.

231151561 is an evil number, because the sum of its binary digits is even.

The product of its digits is 900, while the sum is 25.

The square root of 231151561 is about 15203.6693268434. The cubic root of 231151561 is about 613.7134060918.

The spelling of 231151561 in words is "two hundred thirty-one million, one hundred fifty-one thousand, five hundred sixty-one".