18275981 has 2 divisors, whose sum is σ = 18275982. Its totient is φ = 18275980.

The previous prime is 18275977. The next prime is 18275987. The reversal of 18275981 is 18957281.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18139081 + 136900 = 4259^2 + 370^2 .

It is a cyclic number.

It is not a de Polignac number, because 18275981 - 2² = 18275977 is a prime.

It is a super-2 number, since 2×18275981² = 668022963024722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18275987) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9137990 + 9137991.

It is an arithmetic number, because the mean of its divisors is an integer number (9137991).

Almost surely, 2^18275981 is an apocalyptic number.

It is an amenable number.

18275981 is a deficient number, since it is larger than the sum of its proper divisors (1).

18275981 is an equidigital number, since it uses as much as digits as its factorization.

18275981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 40320, while the sum is 41.

The square root of 18275981 is about 4275.0416372241. The cubic root of 18275981 is about 263.4067496344.

The spelling of 18275981 in words is "eighteen million, two hundred seventy-five thousand, nine hundred eighty-one".