215997 has 4 divisors (see below), whose sum is σ = 288000. Its totient is φ = 143996.

The previous prime is 215983. The next prime is 216023. The reversal of 215997 is 799512.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 215997 - 2⁴ = 215981 is a prime.

It is a D-number.

It is a plaindrome in base 16.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (215927) 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, 35997 + ... + 36002.

It is an arithmetic number, because the mean of its divisors is an integer number (72000).

2²¹⁵⁹⁹⁷ is an apocalyptic number.

It is an amenable number.

215997 is a deficient number, since it is larger than the sum of its proper divisors (72003).

215997 is an equidigital number, since it uses as much as digits as its factorization.

215997 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 72002.

The product of its digits is 5670, while the sum is 33.

The square root of 215997 is about 464.7547740476. The cubic root of 215997 is about 59.9997222209. Note that the first 3 decimals are identical.

The spelling of 215997 in words is "two hundred fifteen thousand, nine hundred ninety-seven".