221712100 has 27 divisors (see below), whose sum is σ = 481438587. Its totient is φ = 88625280.

The previous prime is 221712097. The next prime is 221712109. The reversal of 221712100 is 1217122.

The square root of 221712100 is 14890.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 4 ways, for example, as 41293476 + 180418624 = 6426^2 + 13432^2 .

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (221712109) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 148156 + ... + 149644.

Almost surely, 2^221712100 is an apocalyptic number.

221712100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

221712100 is the 14890-th square number.

It is an amenable number.

221712100 is an abundant number, since it is smaller than the sum of its proper divisors (259726487).

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

221712100 is an equidigital number, since it uses as much as digits as its factorization.

221712100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2992 (or 1496 counting only the distinct ones).

The product of its (nonzero) digits is 56, while the sum is 16.

The cubic root of 221712100 is about 605.2430323823.

Multiplying 221712100 by its sum of digits (16), we get a square (3547393600 = 59560²).

Adding to 221712100 its reverse (1217122), we get a palindrome (222929222).

The spelling of 221712100 in words is "two hundred twenty-one million, seven hundred twelve thousand, one hundred".