18732981 has 4 divisors (see below), whose sum is σ = 24977312. Its totient is φ = 12488652.

The previous prime is 18732977. The next prime is 18732983. The reversal of 18732981 is 18923781.

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 not a de Polignac number, because 18732981 - 2² = 18732977 is a prime.

It is a super-2 number, since 2×18732981² = 701849154292722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18732983) 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, 3122161 + ... + 3122166.

It is an arithmetic number, because the mean of its divisors is an integer number (6244328).

Almost surely, 2^18732981 is an apocalyptic number.

It is an amenable number.

18732981 is a deficient number, since it is larger than the sum of its proper divisors (6244331).

18732981 is an equidigital number, since it uses as much as digits as its factorization.

18732981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6244330.

The product of its digits is 24192, while the sum is 39.

The square root of 18732981 is about 4328.1613879337. The cubic root of 18732981 is about 265.5842384696.

The spelling of 18732981 in words is "eighteen million, seven hundred thirty-two thousand, nine hundred eighty-one".