215697 has 4 divisors (see below), whose sum is σ = 287600. Its totient is φ = 143796.

The previous prime is 215693. The next prime is 215723. The reversal of 215697 is 796512.

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 not a de Polignac number, because 215697 - 2² = 215693 is a prime.

It is a D-number.

It is a Duffinian number.

It is a plaindrome in base 7.

It is not an unprimeable number, because it can be changed into a prime (215693) 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, 35947 + ... + 35952.

It is an arithmetic number, because the mean of its divisors is an integer number (71900).

2²¹⁵⁶⁹⁷ is an apocalyptic number.

It is an amenable number.

215697 is a deficient number, since it is larger than the sum of its proper divisors (71903).

215697 is an equidigital number, since it uses as much as digits as its factorization.

215697 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 71902.

The product of its digits is 3780, while the sum is 30.

The square root of 215697 is about 464.4319110483. The cubic root of 215697 is about 59.9719313156.

The spelling of 215697 in words is "two hundred fifteen thousand, six hundred ninety-seven".