18610561 has 2 divisors, whose sum is σ = 18610562. Its totient is φ = 18610560.

The previous prime is 18610549. The next prime is 18610577. The reversal of 18610561 is 16501681.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18113536 + 497025 = 4256^2 + 705^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18610561 is a prime.

It is not a weakly prime, because it can be changed into another prime (18610061) 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, 9305280 + 9305281.

It is an arithmetic number, because the mean of its divisors is an integer number (9305281).

Almost surely, 2^18610561 is an apocalyptic number.

It is an amenable number.

18610561 is a deficient number, since it is larger than the sum of its proper divisors (1).

18610561 is an equidigital number, since it uses as much as digits as its factorization.

18610561 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1440, while the sum is 28.

The square root of 18610561 is about 4313.9959434381. The cubic root of 18610561 is about 265.0044427877.

The spelling of 18610561 in words is "eighteen million, six hundred ten thousand, five hundred sixty-one".