221992420 has 48 divisors (see below), whose sum is σ = 510311088. Its totient is φ = 80616960.

The previous prime is 221992417. The next prime is 221992427. The reversal of 221992420 is 24299122.

It can be written as a sum of positive squares in 8 ways, for example, as 65642404 + 156350016 = 8102^2 + 12504^2 .

It is not an unprimeable number, because it can be changed into a prime (221992427) 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, 8862 + ... + 22858.

It is an arithmetic number, because the mean of its divisors is an integer number (10631481).

Almost surely, 2^221992420 is an apocalyptic number.

221992420 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 221992420, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (255155544).

221992420 is an abundant number, since it is smaller than the sum of its proper divisors (288318668).

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

221992420 is a wasteful number, since it uses less digits than its factorization.

221992420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14080 (or 14078 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 31.

The square root of 221992420 is about 14899.4100554351. The cubic root of 221992420 is about 605.4980030905.

The spelling of 221992420 in words is "two hundred twenty-one million, nine hundred ninety-two thousand, four hundred twenty".