23181811661 has 2 divisors, whose sum is σ = 23181811662. Its totient is φ = 23181811660.

The previous prime is 23181811637. The next prime is 23181811691. The reversal of 23181811661 is 16611818132.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 22288698436 + 893113225 = 149294^2 + 29885^2 .

It is a cyclic number.

It is not a de Polignac number, because 23181811661 - 2²² = 23177617357 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (23181811691) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 11590905830 + 11590905831.

It is an arithmetic number, because the mean of its divisors is an integer number (11590905831).

Almost surely, 2^23181811661 is an apocalyptic number.

It is an amenable number.

23181811661 is a deficient number, since it is larger than the sum of its proper divisors (1).

23181811661 is an equidigital number, since it uses as much as digits as its factorization.

23181811661 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 13824, while the sum is 38.

The spelling of 23181811661 in words is "twenty-three billion, one hundred eighty-one million, eight hundred eleven thousand, six hundred sixty-one".