221992428 has 96 divisors (see below), whose sum is σ = 626483200. Its totient is φ = 59766336.

The previous prime is 221992427. The next prime is 221992439. The reversal of 221992428 is 824299122.

It is not an unprimeable number, because it can be changed into a prime (221992427) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 585543 + ... + 585921.

Almost surely, 2^221992428 is an apocalyptic number.

221992428 is a gapful number since it is divisible by the number (28) 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 221992428, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (313241600).

221992428 is an abundant number, since it is smaller than the sum of its proper divisors (404490772).

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

221992428 is a wasteful number, since it uses less digits than its factorization.

221992428 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 779 (or 777 counting only the distinct ones).

The product of its digits is 41472, while the sum is 39.

The square root of 221992428 is about 14899.4103239021. The cubic root of 221992428 is about 605.4980103640.

The spelling of 221992428 in words is "two hundred twenty-one million, nine hundred ninety-two thousand, four hundred twenty-eight".