18370981 has 8 divisors (see below), whose sum is σ = 18923544. Its totient is φ = 17821440.

The previous prime is 18370939. The next prime is 18370987. The reversal of 18370981 is 18907381.

It can be written as a sum of positive squares in 4 ways, for example, as 3740356 + 14630625 = 1934^2 + 3825^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 18370981 - 2²³ = 9982373 is a prime.

It is a super-2 number, since 2×18370981² = 674985885804722, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (37).

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 18370981.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18370987) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 18801 + ... + 19753.

It is an arithmetic number, because the mean of its divisors is an integer number (2365443).

Almost surely, 2^18370981 is an apocalyptic number.

It is an amenable number.

18370981 is a deficient number, since it is larger than the sum of its proper divisors (552563).

18370981 is an equidigital number, since it uses as much as digits as its factorization.

18370981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1511.

The product of its (nonzero) digits is 12096, while the sum is 37.

The square root of 18370981 is about 4286.1382385546. The cubic root of 18370981 is about 263.8623641685.

The spelling of 18370981 in words is "eighteen million, three hundred seventy thousand, nine hundred eighty-one".