13721989 has 4 divisors (see below), whose sum is σ = 13733056. Its totient is φ = 13710924.

The previous prime is 13721987. The next prime is 13721993. The reversal of 13721989 is 98912731.

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 a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 98912731 = 89 ⋅1111379.

It is a cyclic number.

It is not a de Polignac number, because 13721989 - 2¹ = 13721987 is a prime.

It is a super-2 number, since 2×13721989² = 376585964232242, which 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 (13721987) 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, 3399 + ... + 6244.

It is an arithmetic number, because the mean of its divisors is an integer number (3433264).

Almost surely, 2^13721989 is an apocalyptic number.

It is an amenable number.

13721989 is a deficient number, since it is larger than the sum of its proper divisors (11067).

13721989 is an equidigital number, since it uses as much as digits as its factorization.

13721989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11066.

The product of its digits is 27216, while the sum is 40.

The square root of 13721989 is about 3704.3203155235. The cubic root of 13721989 is about 239.4082004865.

The spelling of 13721989 in words is "thirteen million, seven hundred twenty-one thousand, nine hundred eighty-nine".