221432420 has 72 divisors (see below), whose sum is σ = 525151032. Its totient is φ = 78312960.

The previous prime is 221432417. The next prime is 221432437. The reversal of 221432420 is 24234122.

It can be written as a sum of positive squares in 4 ways, for example, as 87011584 + 134420836 = 9328^2 + 11594^2 .

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a junction number, because it is equal to n+sod(n) for n = 221432392 and 221432401.

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, 88304 + ... + 90776.

Almost surely, 2^221432420 is an apocalyptic number.

221432420 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 221432420, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (262575516).

221432420 is an abundant number, since it is smaller than the sum of its proper divisors (303718612).

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

221432420 is a wasteful number, since it uses less digits than its factorization.

221432420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2541 (or 2528 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 20.

The square root of 221432420 is about 14880.6054984332. The cubic root of 221432420 is about 604.9884295308.

Adding to 221432420 its reverse (24234122), we get a palindrome (245666542).

The spelling of 221432420 in words is "two hundred twenty-one million, four hundred thirty-two thousand, four hundred twenty".