18868961 has 2 divisors, whose sum is σ = 18868962. Its totient is φ = 18868960.

The previous prime is 18868939. The next prime is 18868973. The reversal of 18868961 is 16986881.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17380561 + 1488400 = 4169^2 + 1220^2 .

It is a cyclic number.

It is not a de Polignac number, because 18868961 - 2¹⁸ = 18606817 is a prime.

It is not a weakly prime, because it can be changed into another prime (18868931) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9434480 + 9434481.

It is an arithmetic number, because the mean of its divisors is an integer number (9434481).

Almost surely, 2^18868961 is an apocalyptic number.

It is an amenable number.

18868961 is a deficient number, since it is larger than the sum of its proper divisors (1).

18868961 is an equidigital number, since it uses as much as digits as its factorization.

18868961 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 165888, while the sum is 47.

The square root of 18868961 is about 4343.8417328443. The cubic root of 18868961 is about 266.2253023591.

The spelling of 18868961 in words is "eighteen million, eight hundred sixty-eight thousand, nine hundred sixty-one".