18253498981 has 4 divisors (see below), whose sum is σ = 18254133964. Its totient is φ = 18252864000.

The previous prime is 18253498969. The next prime is 18253499009. The reversal of 18253498981 is 18989435281.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 18989435281 = 389 ⋅48816029.

It can be written as a sum of positive squares in 2 ways, for example, as 4155736225 + 14097762756 = 64465^2 + 118734^2 .

It is a cyclic number.

It is not a de Polignac number, because 18253498981 - 2⁹ = 18253498469 is a prime.

It is a super-2 number, since 2×18253498981² (a number of 21 digits) 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 (18253408981) 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, 272220 + ... + 332581.

It is an arithmetic number, because the mean of its divisors is an integer number (4563533491).

Almost surely, 2^18253498981 is an apocalyptic number.

It is an amenable number.

18253498981 is a deficient number, since it is larger than the sum of its proper divisors (634983).

18253498981 is an equidigital number, since it uses as much as digits as its factorization.

18253498981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 634982.

The product of its digits is 4976640, while the sum is 58.

The spelling of 18253498981 in words is "eighteen billion, two hundred fifty-three million, four hundred ninety-eight thousand, nine hundred eighty-one".