221243841820 has 24 divisors (see below), whose sum is σ = 464697844128. Its totient is φ = 88481198400.

The previous prime is 221243841803. The next prime is 221243841823. The reversal of 221243841820 is 28148342122.

It is a self number, because there is not a number n which added to its sum of digits gives 221243841820.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221243841823) 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 7 ways as a sum of consecutive naturals, for example, 909811 + ... + 1127050.

It is an arithmetic number, because the mean of its divisors is an integer number (19362410172).

Almost surely, 2^221243841820 is an apocalyptic number.

221243841820 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

221243841820 is an abundant number, since it is smaller than the sum of its proper divisors (243454002308).

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

221243841820 is a wasteful number, since it uses less digits than its factorization.

221243841820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2042301 (or 2042299 counting only the distinct ones).

The product of its (nonzero) digits is 49152, while the sum is 37.

The spelling of 221243841820 in words is "two hundred twenty-one billion, two hundred forty-three million, eight hundred forty-one thousand, eight hundred twenty".