18561401 has 2 divisors, whose sum is σ = 18561402. Its totient is φ = 18561400.

The previous prime is 18561379. The next prime is 18561407. The reversal of 18561401 is 10416581.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16933225 + 1628176 = 4115^2 + 1276^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18561401 is a prime.

It is a Chen prime.

It is equal to p_1184813 and since 18561401 and 1184813 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (18561407) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9280700 + 9280701.

It is an arithmetic number, because the mean of its divisors is an integer number (9280701).

Almost surely, 2^18561401 is an apocalyptic number.

It is an amenable number.

18561401 is a deficient number, since it is larger than the sum of its proper divisors (1).

18561401 is an equidigital number, since it uses as much as digits as its factorization.

18561401 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 960, while the sum is 26.

The square root of 18561401 is about 4308.2944421198. The cubic root of 18561401 is about 264.7708996553.

Adding to 18561401 its reverse (10416581), we get a palindrome (28977982).

The spelling of 18561401 in words is "eighteen million, five hundred sixty-one thousand, four hundred one".