18225661 has 2 divisors, whose sum is σ = 18225662. Its totient is φ = 18225660.

The previous prime is 18225653. The next prime is 18225671. The reversal of 18225661 is 16652281.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13468900 + 4756761 = 3670^2 + 2181^2 .

It is a cyclic number.

It is not a de Polignac number, because 18225661 - 2³ = 18225653 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18225611) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9112830 + 9112831.

It is an arithmetic number, because the mean of its divisors is an integer number (9112831).

Almost surely, 2^18225661 is an apocalyptic number.

It is an amenable number.

18225661 is a deficient number, since it is larger than the sum of its proper divisors (1).

18225661 is an equidigital number, since it uses as much as digits as its factorization.

18225661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5760, while the sum is 31.

The square root of 18225661 is about 4269.1522577673. The cubic root of 18225661 is about 263.1647779245.

The spelling of 18225661 in words is "eighteen million, two hundred twenty-five thousand, six hundred sixty-one".