215081 has 4 divisors (see below), whose sum is σ = 220932. Its totient is φ = 209232.

The previous prime is 215077. The next prime is 215087. The reversal of 215081 is 180512.

215081 = 13² + 14² + ... + 86².

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 173056 + 42025 = 416^2 + 205^2 .

It is a cyclic number.

It is not a de Polignac number, because 215081 - 2² = 215077 is a prime.

It is a super-2 number, since 2×215081² = 92519673122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (215087) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2870 + ... + 2943.

It is an arithmetic number, because the mean of its divisors is an integer number (55233).

2²¹⁵⁰⁸¹ is an apocalyptic number.

It is an amenable number.

215081 is a deficient number, since it is larger than the sum of its proper divisors (5851).

215081 is an equidigital number, since it uses as much as digits as its factorization.

215081 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5850.

The product of its (nonzero) digits is 80, while the sum is 17.

The square root of 215081 is about 463.7682610960. The cubic root of 215081 is about 59.9147864422.

Adding to 215081 its reverse (180512), we get a palindrome (395593).

The spelling of 215081 in words is "two hundred fifteen thousand, eighty-one".