18945661 has 8 divisors (see below), whose sum is σ = 21791360. Its totient is φ = 16134768.

The previous prime is 18945659. The next prime is 18945683. The reversal of 18945661 is 16654981.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 18945661 - 2¹ = 18945659 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18945601) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7521 + ... + 9718.

It is an arithmetic number, because the mean of its divisors is an integer number (2723920).

Almost surely, 2^18945661 is an apocalyptic number.

It is an amenable number.

18945661 is a deficient number, since it is larger than the sum of its proper divisors (2845699).

18945661 is a wasteful number, since it uses less digits than its factorization.

18945661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17403.

The product of its digits is 51840, while the sum is 40.

The square root of 18945661 is about 4352.6613697829. The cubic root of 18945661 is about 266.5855390364.

The spelling of 18945661 in words is "eighteen million, nine hundred forty-five thousand, six hundred sixty-one".