215906 has 8 divisors (see below), whose sum is σ = 331884. Its totient is φ = 105280.

The previous prime is 215899. The next prime is 215909. The reversal of 215906 is 609512.

215906 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 172225 + 43681 = 415^2 + 209^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (215909) 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, 1235 + ... + 1398.

2²¹⁵⁹⁰⁶ is an apocalyptic number.

215906 is a deficient number, since it is larger than the sum of its proper divisors (115978).

215906 is a wasteful number, since it uses less digits than its factorization.

215906 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2676.

The product of its (nonzero) digits is 540, while the sum is 23.

The square root of 215906 is about 464.6568626417. The cubic root of 215906 is about 59.9912950334.

The spelling of 215906 in words is "two hundred fifteen thousand, nine hundred six".