13520921 has 2 divisors, whose sum is σ = 13520922. Its totient is φ = 13520920.

The previous prime is 13520917. The next prime is 13520953. The reversal of 13520921 is 12902531.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12880921 + 640000 = 3589^2 + 800^2 .

It is a cyclic number.

It is not a de Polignac number, because 13520921 - 2² = 13520917 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (13520911) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6760460 + 6760461.

It is an arithmetic number, because the mean of its divisors is an integer number (6760461).

Almost surely, 2^13520921 is an apocalyptic number.

It is an amenable number.

13520921 is a deficient number, since it is larger than the sum of its proper divisors (1).

13520921 is an equidigital number, since it uses as much as digits as its factorization.

13520921 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 540, while the sum is 23.

The square root of 13520921 is about 3677.0804995268. The cubic root of 13520921 is about 238.2330943765.

It can be divided in two parts, 13520 and 921, that added together give a palindrome (14441).

The spelling of 13520921 in words is "thirteen million, five hundred twenty thousand, nine hundred twenty-one".