23015561 has 2 divisors, whose sum is σ = 23015562. Its totient is φ = 23015560.

The previous prime is 23015549. The next prime is 23015563. The reversal of 23015561 is 16551032.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21529600 + 1485961 = 4640^2 + 1219^2 .

It is a cyclic number.

It is not a de Polignac number, because 23015561 - 2⁶ = 23015497 is a prime.

It is a Sophie Germain prime.

Together with 23015563, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (23015563) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 11507780 + 11507781.

It is an arithmetic number, because the mean of its divisors is an integer number (11507781).

Almost surely, 2^23015561 is an apocalyptic number.

It is an amenable number.

23015561 is a deficient number, since it is larger than the sum of its proper divisors (1).

23015561 is an equidigital number, since it uses as much as digits as its factorization.

23015561 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 900, while the sum is 23.

The square root of 23015561 is about 4797.4535953983. The cubic root of 23015561 is about 284.4508189094.

Adding to 23015561 its reverse (16551032), we get a palindrome (39566593).

The spelling of 23015561 in words is "twenty-three million, fifteen thousand, five hundred sixty-one".