221311530 has 48 divisors (see below), whose sum is σ = 627722784. Its totient is φ = 53651040.

The previous prime is 221311523. The next prime is 221311547. The reversal of 221311530 is 35113122.

221311530 is a `hidden beast` number, since 2 + 2 + 131 + 1 + 530 = 666.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 110784 + ... + 112763.

It is an arithmetic number, because the mean of its divisors is an integer number (13077558).

Almost surely, 2^221311530 is an apocalyptic number.

221311530 is an abundant number, since it is smaller than the sum of its proper divisors (406411254).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

221311530 is a wasteful number, since it uses less digits than its factorization.

221311530 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 223571 (or 223568 counting only the distinct ones).

The product of its (nonzero) digits is 180, while the sum is 18.

The square root of 221311530 is about 14876.5429451872. The cubic root of 221311530 is about 604.8783126158.

Adding to 221311530 its reverse (35113122), we get a palindrome (256424652).

It can be divided in two parts, 221311 and 530, that added together give a square (221841 = 471²).

The spelling of 221311530 in words is "two hundred twenty-one million, three hundred eleven thousand, five hundred thirty".