23805917521 has 2 divisors, whose sum is σ = 23805917522. Its totient is φ = 23805917520.

The previous prime is 23805917459. The next prime is 23805917567. The reversal of 23805917521 is 12571950832.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 22034433600 + 1771483921 = 148440^2 + 42089^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-23805917521 is a prime.

It is not a weakly prime, because it can be changed into another prime (23805917221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 11902958760 + 11902958761.

It is an arithmetic number, because the mean of its divisors is an integer number (11902958761).

Almost surely, 2^23805917521 is an apocalyptic number.

It is an amenable number.

23805917521 is a deficient number, since it is larger than the sum of its proper divisors (1).

23805917521 is an equidigital number, since it uses as much as digits as its factorization.

23805917521 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 151200, while the sum is 43.

The spelling of 23805917521 in words is "twenty-three billion, eight hundred five million, nine hundred seventeen thousand, five hundred twenty-one".