13721993 has 2 divisors, whose sum is σ = 13721994. Its totient is φ = 13721992.

The previous prime is 13721987. The next prime is 13722019. The reversal of 13721993 is 39912731.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 10582009 + 3139984 = 3253^2 + 1772^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-13721993 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (13721093) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6860996 + 6860997.

It is an arithmetic number, because the mean of its divisors is an integer number (6860997).

Almost surely, 2^13721993 is an apocalyptic number.

It is an amenable number.

13721993 is a deficient number, since it is larger than the sum of its proper divisors (1).

13721993 is an equidigital number, since it uses as much as digits as its factorization.

13721993 is an evil number, because the sum of its binary digits is even.

The product of its digits is 10206, while the sum is 35.

The square root of 13721993 is about 3704.3208554336. The cubic root of 13721993 is about 239.4082237492.

The spelling of 13721993 in words is "thirteen million, seven hundred twenty-one thousand, nine hundred ninety-three".