23256781 has 2 divisors, whose sum is σ = 23256782. Its totient is φ = 23256780.

The previous prime is 23256773. The next prime is 23256803. The reversal of 23256781 is 18765232.

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., 18783556 + 4473225 = 4334^2 + 2115^2 .

It is a cyclic number.

It is not a de Polignac number, because 23256781 - 2³ = 23256773 is a prime.

It is a super-2 number, since 2×23256781² = 1081755724963922, which contains 22 as substring.

It is an alternating number because its digits alternate between even and odd.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (23256281) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 11628390 + 11628391.

It is an arithmetic number, because the mean of its divisors is an integer number (11628391).

Almost surely, 2^23256781 is an apocalyptic number.

It is an amenable number.

23256781 is a deficient number, since it is larger than the sum of its proper divisors (1).

23256781 is an equidigital number, since it uses as much as digits as its factorization.

23256781 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 20160, while the sum is 34.

The square root of 23256781 is about 4822.5284861782. The cubic root of 23256781 is about 285.4411184716.

The spelling of 23256781 in words is "twenty-three million, two hundred fifty-six thousand, seven hundred eighty-one".