213731 has 8 divisors (see below), whose sum is σ = 257280. Its totient is φ = 173448.

The previous prime is 213727. The next prime is 213737. The reversal of 213731 is 137312.

213731 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 213731 - 2² = 213727 is a prime.

It is a super-2 number, since 2×213731² = 91361880722, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (213737) 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, 671 + ... + 936.

It is an arithmetic number, because the mean of its divisors is an integer number (32160).

2²¹³⁷³¹ is an apocalyptic number.

213731 is a deficient number, since it is larger than the sum of its proper divisors (43549).

213731 is a wasteful number, since it uses less digits than its factorization.

213731 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1633.

The product of its digits is 126, while the sum is 17.

The square root of 213731 is about 462.3105017194. The cubic root of 213731 is about 59.7891674356.

The spelling of 213731 in words is "two hundred thirteen thousand, seven hundred thirty-one".