220731 has 16 divisors (see below), whose sum is σ = 351744. Its totient is φ = 120384.

The previous prime is 220721. The next prime is 220747. The reversal of 220731 is 137022.

220731 = 119² + 120² + ... + 132².

It is not a de Polignac number, because 220731 - 2⁵ = 220699 is a prime.

It is a super-2 number, since 2×220731² = 97444348722, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 220731.

It is not an unprimeable number, because it can be changed into a prime (220721) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 255 + ... + 711.

It is an arithmetic number, because the mean of its divisors is an integer number (21984).

2²²⁰⁷³¹ is an apocalyptic number.

220731 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

220731 is a deficient number, since it is larger than the sum of its proper divisors (131013).

220731 is a wasteful number, since it uses less digits than its factorization.

220731 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 490.

The product of its (nonzero) digits is 84, while the sum is 15.

The square root of 220731 is about 469.8201783661. The cubic root of 220731 is about 60.4348957016.

Adding to 220731 its reverse (137022), we get a palindrome (357753).

The spelling of 220731 in words is "two hundred twenty thousand, seven hundred thirty-one".