18597661 has 2 divisors, whose sum is σ = 18597662. Its totient is φ = 18597660.

The previous prime is 18597617. The next prime is 18597697. The reversal of 18597661 is 16679581.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 10791225 + 7806436 = 3285^2 + 2794^2 .

It is a cyclic number.

It is not a de Polignac number, because 18597661 - 2¹³ = 18589469 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18597611) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9298830 + 9298831.

It is an arithmetic number, because the mean of its divisors is an integer number (9298831).

Almost surely, 2^18597661 is an apocalyptic number.

It is an amenable number.

18597661 is a deficient number, since it is larger than the sum of its proper divisors (1).

18597661 is an equidigital number, since it uses as much as digits as its factorization.

18597661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 90720, while the sum is 43.

The square root of 18597661 is about 4312.5005507246. The cubic root of 18597661 is about 264.9431989331.

The spelling of 18597661 in words is "eighteen million, five hundred ninety-seven thousand, six hundred sixty-one".