215513 has 4 divisors (see below), whose sum is σ = 219108. Its totient is φ = 211920.

The previous prime is 215507. The next prime is 215521. The reversal of 215513 is 315512.

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

It can be written as a sum of positive squares in 2 ways, for example, as 80089 + 135424 = 283^2 + 368^2 .

It is a cyclic number.

It is not a de Polignac number, because 215513 - 2⁴ = 215497 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 215491 and 215500.

It is not an unprimeable number, because it can be changed into a prime (215503) 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, 1706 + ... + 1827.

It is an arithmetic number, because the mean of its divisors is an integer number (54777).

2²¹⁵⁵¹³ is an apocalyptic number.

It is an amenable number.

215513 is a deficient number, since it is larger than the sum of its proper divisors (3595).

215513 is an equidigital number, since it uses as much as digits as its factorization.

215513 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3594.

The product of its digits is 150, while the sum is 17.

The square root of 215513 is about 464.2337773148. The cubic root of 215513 is about 59.9548734759.

Subtracting from 215513 its sum of digits (17), we obtain a triangular number (215496 = T₆₅₆).

Subtracting 215513 from its reverse (315512), we obtain a palindrome (99999).

The spelling of 215513 in words is "two hundred fifteen thousand, five hundred thirteen".