18870981 has 4 divisors (see below), whose sum is σ = 25161312. Its totient is φ = 12580652.

The previous prime is 18870959. The next prime is 18870997. The reversal of 18870981 is 18907881.

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 not a de Polignac number, because 18870981 - 2⁵ = 18870949 is a prime.

It is a super-2 number, since 2×18870981² = 712227847804722, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18870931) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3145161 + ... + 3145166.

It is an arithmetic number, because the mean of its divisors is an integer number (6290328).

Almost surely, 2^18870981 is an apocalyptic number.

It is an amenable number.

18870981 is a deficient number, since it is larger than the sum of its proper divisors (6290331).

18870981 is an equidigital number, since it uses as much as digits as its factorization.

18870981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6290330.

The product of its (nonzero) digits is 32256, while the sum is 42.

The square root of 18870981 is about 4344.0742396971. The cubic root of 18870981 is about 266.2348021919.

The spelling of 18870981 in words is "eighteen million, eight hundred seventy thousand, nine hundred eighty-one".