13499981 has 4 divisors (see below), whose sum is σ = 14727264. Its totient is φ = 12272700.

The previous prime is 13499939. The next prime is 13499999. The reversal of 13499981 is 18999431.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 18999431 = 11 ⋅1727221.

It is a de Polignac number, because none of the positive numbers 2^k-13499981 is a prime.

It is a super-2 number, since 2×13499981² = 364498974000722, 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 (13499081) 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, 613625 + ... + 613646.

It is an arithmetic number, because the mean of its divisors is an integer number (3681816).

Almost surely, 2^13499981 is an apocalyptic number.

13499981 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

13499981 is a deficient number, since it is larger than the sum of its proper divisors (1227283).

13499981 is a wasteful number, since it uses less digits than its factorization.

13499981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1227282.

The product of its digits is 69984, while the sum is 44.

The square root of 13499981 is about 3674.2320286014. The cubic root of 13499981 is about 238.1100460892.

It can be divided in two parts, 13 and 499981, that added together give a palindrome (499994).

The spelling of 13499981 in words is "thirteen million, four hundred ninety-nine thousand, nine hundred eighty-one".