18985961 has 4 divisors (see below), whose sum is σ = 19131024. Its totient is φ = 18840900.

The previous prime is 18985951. The next prime is 18985969. The reversal of 18985961 is 16958981.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18985961 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18985969) 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 3 ways as a sum of consecutive naturals, for example, 72335 + ... + 72596.

It is an arithmetic number, because the mean of its divisors is an integer number (4782756).

Almost surely, 2^18985961 is an apocalyptic number.

It is an amenable number.

18985961 is a deficient number, since it is larger than the sum of its proper divisors (145063).

18985961 is a wasteful number, since it uses less digits than its factorization.

18985961 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 145062.

The product of its digits is 155520, while the sum is 47.

The square root of 18985961 is about 4357.2882622108. The cubic root of 18985961 is about 266.7744264138.

The spelling of 18985961 in words is "eighteen million, nine hundred eighty-five thousand, nine hundred sixty-one".