13668521 has 2 divisors, whose sum is σ = 13668522. Its totient is φ = 13668520.

The previous prime is 13668517. The next prime is 13668547. The reversal of 13668521 is 12586631.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11978521 + 1690000 = 3461^2 + 1300^2 .

It is a cyclic number.

It is not a de Polignac number, because 13668521 - 2² = 13668517 is a prime.

It is not a weakly prime, because it can be changed into another prime (13661521) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6834260 + 6834261.

It is an arithmetic number, because the mean of its divisors is an integer number (6834261).

Almost surely, 2^13668521 is an apocalyptic number.

It is an amenable number.

13668521 is a deficient number, since it is larger than the sum of its proper divisors (1).

13668521 is an equidigital number, since it uses as much as digits as its factorization.

13668521 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 8640, while the sum is 32.

The square root of 13668521 is about 3697.0962930386. The cubic root of 13668521 is about 239.0968428114.

The spelling of 13668521 in words is "thirteen million, six hundred sixty-eight thousand, five hundred twenty-one".