18998961 has 16 divisors (see below), whose sum is σ = 25878528. Its totient is φ = 12395600.

The previous prime is 18998957. The next prime is 18998977. The reversal of 18998961 is 16989981.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 18998961 - 2² = 18998957 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (18998921) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 40450 + ... + 40916.

It is an arithmetic number, because the mean of its divisors is an integer number (1617408).

Almost surely, 2^18998961 is an apocalyptic number.

It is an amenable number.

18998961 is a deficient number, since it is larger than the sum of its proper divisors (6879567).

18998961 is a wasteful number, since it uses less digits than its factorization.

18998961 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 732.

The product of its digits is 279936, while the sum is 51.

The square root of 18998961 is about 4358.7797604375. The cubic root of 18998961 is about 266.8353008023.

The spelling of 18998961 in words is "eighteen million, nine hundred ninety-eight thousand, nine hundred sixty-one".