18260981 has 4 divisors (see below), whose sum is σ = 18890700. Its totient is φ = 17631264.

The previous prime is 18260959. The next prime is 18260989. The reversal of 18260981 is 18906281.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 18906281 = 263 ⋅71887.

It can be written as a sum of positive squares in 2 ways, for example, as 8439025 + 9821956 = 2905^2 + 3134^2 .

It is a cyclic number.

It is not a de Polignac number, because 18260981 - 2¹⁰ = 18259957 is a prime.

It is a super-2 number, since 2×18260981² = 666926854164722, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18260989) 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, 314816 + ... + 314873.

It is an arithmetic number, because the mean of its divisors is an integer number (4722675).

Almost surely, 2^18260981 is an apocalyptic number.

It is an amenable number.

18260981 is a deficient number, since it is larger than the sum of its proper divisors (629719).

18260981 is an equidigital number, since it uses as much as digits as its factorization.

18260981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 629718.

The product of its (nonzero) digits is 6912, while the sum is 35.

The square root of 18260981 is about 4273.2869082242. The cubic root of 18260981 is about 263.3346662682.

The spelling of 18260981 in words is "eighteen million, two hundred sixty thousand, nine hundred eighty-one".