13215651 has 4 divisors (see below), whose sum is σ = 17620872. Its totient is φ = 8810432.

The previous prime is 13215617. The next prime is 13215661. The reversal of 13215651 is 15651231.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 13215651 - 2¹⁴ = 13199267 is a prime.

It is not an unprimeable number, because it can be changed into a prime (13215661) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2202606 + ... + 2202611.

It is an arithmetic number, because the mean of its divisors is an integer number (4405218).

Almost surely, 2^13215651 is an apocalyptic number.

13215651 is a deficient number, since it is larger than the sum of its proper divisors (4405221).

13215651 is an equidigital number, since it uses as much as digits as its factorization.

13215651 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4405220.

The product of its digits is 900, while the sum is 24.

The square root of 13215651 is about 3635.3336848218. Note that the first 3 decimals coincide. The cubic root of 13215651 is about 236.4265185078.

Adding to 13215651 its reverse (15651231), we get a palindrome (28866882).

It can be divided in two parts, 132156 and 51, that multiplied together give a triangular number (6739956 = T₃₆₇₁).

The spelling of 13215651 in words is "thirteen million, two hundred fifteen thousand, six hundred fifty-one".