18495981 has 18 divisors (see below), whose sum is σ = 31079022. Its totient is φ = 10568880.

The previous prime is 18495973. The next prime is 18495989. The reversal of 18495981 is 18959481.

18495981 is a `hidden beast` number, since 18 + 49 + 598 + 1 = 666.

It is an interprime number because it is at equal distance from previous prime (18495973) and next prime (18495989).

It can be written as a sum of positive squares in only one way, i.e., 10458756 + 8037225 = 3234^2 + 2835^2 .

It is not a de Polignac number, because 18495981 - 2³ = 18495973 is a prime.

It is a super-2 number, since 2×18495981² = 684202626304722, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18495989) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 20530 + ... + 21411.

Almost surely, 2^18495981 is an apocalyptic number.

It is an amenable number.

18495981 is a deficient number, since it is larger than the sum of its proper divisors (12583041).

18495981 is a wasteful number, since it uses less digits than its factorization.

18495981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41961 (or 41951 counting only the distinct ones).

The product of its digits is 103680, while the sum is 45.

The square root of 18495981 is about 4300.6954088845. The cubic root of 18495981 is about 264.4594701830.

The spelling of 18495981 in words is "eighteen million, four hundred ninety-five thousand, nine hundred eighty-one".