215831 has 8 divisors (see below), whose sum is σ = 269184. Its totient is φ = 168120.

The previous prime is 215827. The next prime is 215833. The reversal of 215831 is 138512.

215831 = T₃₃ + T₃₄ + ... + T₁₀₉.

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

It is a cyclic number.

It is not a de Polignac number, because 215831 - 2² = 215827 is a prime.

It is a super-2 number, since 2×215831² = 93166041122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 215831.

It is not an unprimeable number, because it can be changed into a prime (215833) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1325 + ... + 1478.

It is an arithmetic number, because the mean of its divisors is an integer number (33648).

2²¹⁵⁸³¹ is an apocalyptic number.

215831 is a deficient number, since it is larger than the sum of its proper divisors (53353).

215831 is a wasteful number, since it uses less digits than its factorization.

215831 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2821.

The product of its digits is 240, while the sum is 20.

The square root of 215831 is about 464.5761509161. The cubic root of 215831 is about 59.9843477690.

The spelling of 215831 in words is "two hundred fifteen thousand, eight hundred thirty-one".