13721997 has 4 divisors (see below), whose sum is σ = 18296000. Its totient is φ = 9147996.

The previous prime is 13721993. The next prime is 13722019. The reversal of 13721997 is 79912731.

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.

It is not a de Polignac number, because 13721997 - 2² = 13721993 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13721993) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2286997 + ... + 2287002.

It is an arithmetic number, because the mean of its divisors is an integer number (4574000).

Almost surely, 2^13721997 is an apocalyptic number.

It is an amenable number.

13721997 is a deficient number, since it is larger than the sum of its proper divisors (4574003).

13721997 is an equidigital number, since it uses as much as digits as its factorization.

13721997 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4574002.

The product of its digits is 23814, while the sum is 39.

The square root of 13721997 is about 3704.3213953436. The cubic root of 13721997 is about 239.4082470119.

The spelling of 13721997 in words is "thirteen million, seven hundred twenty-one thousand, nine hundred ninety-seven".