221881920 has 224 divisors, whose sum is σ = 792675072. Its totient is φ = 52174848.

The previous prime is 221881889. The next prime is 221881921. The reversal of 221881920 is 29188122.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221881921) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 286654 + ... + 287426.

It is an arithmetic number, because the mean of its divisors is an integer number (3538728).

Almost surely, 2^221881920 is an apocalyptic number.

221881920 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 221881920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (396337536).

221881920 is an abundant number, since it is smaller than the sum of its proper divisors (570793152).

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

221881920 is a wasteful number, since it uses less digits than its factorization.

221881920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 829 (or 819 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 33.

The square root of 221881920 is about 14895.7013933551. The cubic root of 221881920 is about 605.3975212305.

The spelling of 221881920 in words is "two hundred twenty-one million, eight hundred eighty-one thousand, nine hundred twenty".