13455809981 has 4 divisors (see below), whose sum is σ = 13456446492. Its totient is φ = 13455173472.

The previous prime is 13455809977. The next prime is 13455809999. The reversal of 13455809981 is 18990855431.

It is a happy number.

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 9261175225 + 4194634756 = 96235^2 + 64766^2 .

It is a cyclic number.

It is not a de Polignac number, because 13455809981 - 2² = 13455809977 is a prime.

It is a super-2 number, since 2×13455809981² (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 (13455809911) 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, 285416 + ... + 329201.

It is an arithmetic number, because the mean of its divisors is an integer number (3364111623).

Almost surely, 2^13455809981 is an apocalyptic number.

It is an amenable number.

13455809981 is a deficient number, since it is larger than the sum of its proper divisors (636511).

13455809981 is an equidigital number, since it uses as much as digits as its factorization.

13455809981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 636510.

The product of its (nonzero) digits is 1555200, while the sum is 53.

The spelling of 13455809981 in words is "thirteen billion, four hundred fifty-five million, eight hundred nine thousand, nine hundred eighty-one".