23181989 has 2 divisors, whose sum is σ = 23181990. Its totient is φ = 23181988.

The previous prime is 23181979. The next prime is 23182009. The reversal of 23181989 is 98918132.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16265089 + 6916900 = 4033^2 + 2630^2 .

It is a cyclic number.

It is not a de Polignac number, because 23181989 - 2⁸ = 23181733 is a prime.

It is a super-2 number, since 2×23181989² = 1074809227992242, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (23181959) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 11590994 + 11590995.

It is an arithmetic number, because the mean of its divisors is an integer number (11590995).

Almost surely, 2^23181989 is an apocalyptic number.

It is an amenable number.

23181989 is a deficient number, since it is larger than the sum of its proper divisors (1).

23181989 is an equidigital number, since it uses as much as digits as its factorization.

23181989 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 31104, while the sum is 41.

The square root of 23181989 is about 4814.7678033317. The cubic root of 23181989 is about 285.1348043923.

The spelling of 23181989 in words is "twenty-three million, one hundred eighty-one thousand, nine hundred eighty-nine".