23091781 has 2 divisors, whose sum is σ = 23091782. Its totient is φ = 23091780.

The previous prime is 23091773. The next prime is 23091787. The reversal of 23091781 is 18719032.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13068225 + 10023556 = 3615^2 + 3166^2 .

It is a cyclic number.

It is not a de Polignac number, because 23091781 - 2³ = 23091773 is a prime.

It is a super-2 number, since 2×23091781² = 1066460699503922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (23091787) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 11545890 + 11545891.

It is an arithmetic number, because the mean of its divisors is an integer number (11545891).

Almost surely, 2^23091781 is an apocalyptic number.

It is an amenable number.

23091781 is a deficient number, since it is larger than the sum of its proper divisors (1).

23091781 is an equidigital number, since it uses as much as digits as its factorization.

23091781 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3024, while the sum is 31.

The square root of 23091781 is about 4805.3908269776. The cubic root of 23091781 is about 284.7644755708.

The spelling of 23091781 in words is "twenty-three million, ninety-one thousand, seven hundred eighty-one".