13215905 has 4 divisors (see below), whose sum is σ = 15859092. Its totient is φ = 10572720.

The previous prime is 13215901. The next prime is 13215911. The reversal of 13215905 is 50951231.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 50951231 = 29 ⋅1756939.

It can be written as a sum of positive squares in 2 ways, for example, as 1430416 + 11785489 = 1196^2 + 3433^2 .

It is not a de Polignac number, because 13215905 - 2² = 13215901 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (13215901) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1321586 + ... + 1321595.

It is an arithmetic number, because the mean of its divisors is an integer number (3964773).

Almost surely, 2^13215905 is an apocalyptic number.

It is an amenable number.

13215905 is a deficient number, since it is larger than the sum of its proper divisors (2643187).

13215905 is an equidigital number, since it uses as much as digits as its factorization.

13215905 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2643186.

The product of its (nonzero) digits is 1350, while the sum is 26.

The square root of 13215905 is about 3635.3686195488. The cubic root of 13215905 is about 236.4280331753.

The spelling of 13215905 in words is "thirteen million, two hundred fifteen thousand, nine hundred five".