13215421 has 2 divisors, whose sum is σ = 13215422. Its totient is φ = 13215420.

The previous prime is 13215383. The next prime is 13215427. The reversal of 13215421 is 12451231.

13215421 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 6687396 + 6528025 = 2586^2 + 2555^2 .

It is a cyclic number.

It is not a de Polignac number, because 13215421 - 2⁹ = 13214909 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (13215427) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6607710 + 6607711.

It is an arithmetic number, because the mean of its divisors is an integer number (6607711).

Almost surely, 2^13215421 is an apocalyptic number.

It is an amenable number.

13215421 is a deficient number, since it is larger than the sum of its proper divisors (1).

13215421 is an equidigital number, since it uses as much as digits as its factorization.

13215421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 240, while the sum is 19.

The square root of 13215421 is about 3635.3020507243. The cubic root of 13215421 is about 236.4251469418.

Adding to 13215421 its reverse (12451231), we get a palindrome (25666652).

The spelling of 13215421 in words is "thirteen million, two hundred fifteen thousand, four hundred twenty-one".