18981453569 has 4 divisors (see below), whose sum is σ = 20441565396. Its totient is φ = 17521341744.

The previous prime is 18981453563. The next prime is 18981453577. The reversal of 18981453569 is 96535418981.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 8443404544 + 10538049025 = 91888^2 + 102655^2 .

It is a cyclic number.

It is not a de Polignac number, because 18981453569 - 2⁴ = 18981453553 is a prime.

It is a super-2 number, since 2×18981453569² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (18981453563) 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, 730055894 + ... + 730055919.

It is an arithmetic number, because the mean of its divisors is an integer number (5110391349).

Almost surely, 2^18981453569 is an apocalyptic number.

It is an amenable number.

18981453569 is a deficient number, since it is larger than the sum of its proper divisors (1460111827).

18981453569 is a wasteful number, since it uses less digits than its factorization.

18981453569 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1460111826.

The product of its digits is 9331200, while the sum is 59.

The spelling of 18981453569 in words is "eighteen billion, nine hundred eighty-one million, four hundred fifty-three thousand, five hundred sixty-nine".