18994661 has 32 divisors (see below), whose sum is σ = 25067520. Its totient is φ = 13996800.

The previous prime is 18994643. The next prime is 18994663. The reversal of 18994661 is 16649981.

It is a cyclic number.

It is not a de Polignac number, because 18994661 - 2⁶ = 18994597 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18994663) 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 in 31 ways as a sum of consecutive naturals, for example, 69956 + ... + 70226.

It is an arithmetic number, because the mean of its divisors is an integer number (783360).

Almost surely, 2^18994661 is an apocalyptic number.

It is an amenable number.

18994661 is a deficient number, since it is larger than the sum of its proper divisors (6072859).

18994661 is a wasteful number, since it uses less digits than its factorization.

18994661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 345.

The product of its digits is 93312, while the sum is 44.

The square root of 18994661 is about 4358.2864752102. The cubic root of 18994661 is about 266.8151685019.

The spelling of 18994661 in words is "eighteen million, nine hundred ninety-four thousand, six hundred sixty-one".