13215551 has 4 divisors (see below), whose sum is σ = 13296792. Its totient is φ = 13134312.

The previous prime is 13215541. The next prime is 13215569. The reversal of 13215551 is 15551231.

It is a happy number.

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 13215551 - 2¹⁰ = 13214527 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13215541) 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, 40376 + ... + 40701.

It is an arithmetic number, because the mean of its divisors is an integer number (3324198).

Almost surely, 2^13215551 is an apocalyptic number.

13215551 is a deficient number, since it is larger than the sum of its proper divisors (81241).

13215551 is an equidigital number, since it uses as much as digits as its factorization.

13215551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 81240.

The product of its digits is 750, while the sum is 23.

The square root of 13215551 is about 3635.3199309002. The cubic root of 13215551 is about 236.4259221767.

Adding to 13215551 its reverse (15551231), we get a palindrome (28766782).

The spelling of 13215551 in words is "thirteen million, two hundred fifteen thousand, five hundred fifty-one".