221430531 has 16 divisors (see below), whose sum is σ = 337747968. Its totient is φ = 126408000.

The previous prime is 221430527. The next prime is 221430569. The reversal of 221430531 is 135034122.

It is not a de Polignac number, because 221430531 - 2² = 221430527 is a prime.

It is a super-2 number, since 2×221430531² = 98062960117883922, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a junction number, because it is equal to n+sod(n) for n = 221430498 and 221430507.

It is not an unprimeable number, because it can be changed into a prime (221431531) 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, 19591 + ... + 28751.

It is an arithmetic number, because the mean of its divisors is an integer number (21109248).

Almost surely, 2^221430531 is an apocalyptic number.

221430531 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

221430531 is a deficient number, since it is larger than the sum of its proper divisors (116317437).

221430531 is a wasteful number, since it uses less digits than its factorization.

221430531 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10322.

The product of its (nonzero) digits is 720, while the sum is 21.

The square root of 221430531 is about 14880.5420264183. The cubic root of 221430531 is about 604.9867091769.

Adding to 221430531 its reverse (135034122), we get a palindrome (356464653).

The spelling of 221430531 in words is "two hundred twenty-one million, four hundred thirty thousand, five hundred thirty-one".