23531509 has 2 divisors, whose sum is σ = 23531510. Its totient is φ = 23531508.

The previous prime is 23531491. The next prime is 23531513. The reversal of 23531509 is 90513532.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20566225 + 2965284 = 4535^2 + 1722^2 .

It is a cyclic number.

It is not a de Polignac number, because 23531509 - 2¹³ = 23523317 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (23531549) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 11765754 + 11765755.

It is an arithmetic number, because the mean of its divisors is an integer number (11765755).

Almost surely, 2^23531509 is an apocalyptic number.

It is an amenable number.

23531509 is a deficient number, since it is larger than the sum of its proper divisors (1).

23531509 is an equidigital number, since it uses as much as digits as its factorization.

23531509 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4050, while the sum is 28.

The square root of 23531509 is about 4850.9286739757. The cubic root of 23531509 is about 286.5606757672.

The spelling of 23531509 in words is "twenty-three million, five hundred thirty-one thousand, five hundred nine".