13917249721 has 2 divisors, whose sum is σ = 13917249722. Its totient is φ = 13917249720.

The previous prime is 13917249673. The next prime is 13917249757. The reversal of 13917249721 is 12794271931.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12719328400 + 1197921321 = 112780^2 + 34611^2 .

It is a cyclic number.

It is not a de Polignac number, because 13917249721 - 2¹³ = 13917241529 is a prime.

It is not a weakly prime, because it can be changed into another prime (13917249781) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6958624860 + 6958624861.

It is an arithmetic number, because the mean of its divisors is an integer number (6958624861).

Almost surely, 2^13917249721 is an apocalyptic number.

It is an amenable number.

13917249721 is a deficient number, since it is larger than the sum of its proper divisors (1).

13917249721 is an equidigital number, since it uses as much as digits as its factorization.

13917249721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 190512, while the sum is 46.

The spelling of 13917249721 in words is "thirteen billion, nine hundred seventeen million, two hundred forty-nine thousand, seven hundred twenty-one".