221641920 has 280 divisors, whose sum is σ = 836456544. Its totient is φ = 55517184.

The previous prime is 221641883. The next prime is 221641969. The reversal of 221641920 is 29146122.

221641920 is a `hidden beast` number, since 221 + 6 + 419 + 20 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 440389 + ... + 440891.

Almost surely, 2^221641920 is an apocalyptic number.

221641920 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 221641920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (418228272).

221641920 is an abundant number, since it is smaller than the sum of its proper divisors (614814624).

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

221641920 is a wasteful number, since it uses less digits than its factorization.

221641920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 549 (or 530 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 27.

The square root of 221641920 is about 14887.6431983038. The cubic root of 221641920 is about 605.1791651139.

The spelling of 221641920 in words is "two hundred twenty-one million, six hundred forty-one thousand, nine hundred twenty".