23138509 has 2 divisors, whose sum is σ = 23138510. Its totient is φ = 23138508.

The previous prime is 23138501. The next prime is 23138519. The reversal of 23138509 is 90583132.

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., 18062500 + 5076009 = 4250^2 + 2253^2 .

It is a cyclic number.

It is not a de Polignac number, because 23138509 - 2³ = 23138501 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (23138501) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 11569254 + 11569255.

It is an arithmetic number, because the mean of its divisors is an integer number (11569255).

Almost surely, 2^23138509 is an apocalyptic number.

It is an amenable number.

23138509 is a deficient number, since it is larger than the sum of its proper divisors (1).

23138509 is an equidigital number, since it uses as much as digits as its factorization.

23138509 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6480, while the sum is 31.

The square root of 23138509 is about 4810.2504092822. The cubic root of 23138509 is about 284.9564271131.

The spelling of 23138509 in words is "twenty-three million, one hundred thirty-eight thousand, five hundred nine".