18289561 has 2 divisors, whose sum is σ = 18289562. Its totient is φ = 18289560.

The previous prime is 18289549. The next prime is 18289591. The reversal of 18289561 is 16598281.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14107536 + 4182025 = 3756^2 + 2045^2 .

It is a cyclic number.

It is not a de Polignac number, because 18289561 - 2²¹ = 16192409 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (18289541) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9144780 + 9144781.

It is an arithmetic number, because the mean of its divisors is an integer number (9144781).

Almost surely, 2^18289561 is an apocalyptic number.

It is an amenable number.

18289561 is a deficient number, since it is larger than the sum of its proper divisors (1).

18289561 is an equidigital number, since it uses as much as digits as its factorization.

18289561 is an evil number, because the sum of its binary digits is even.

The product of its digits is 34560, while the sum is 40.

The square root of 18289561 is about 4276.6296309126. The cubic root of 18289561 is about 263.4719750988.

The spelling of 18289561 in words is "eighteen million, two hundred eighty-nine thousand, five hundred sixty-one".