221849820 has 48 divisors (see below), whose sum is σ = 690201120. Its totient is φ = 59159808.

The previous prime is 221849819. The next prime is 221849821. The reversal of 221849820 is 28948122.

221849820 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (221849819) and next prime (221849821).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221849821) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 204877 + ... + 205956.

It is an arithmetic number, because the mean of its divisors is an integer number (14379190).

Almost surely, 2^221849820 is an apocalyptic number.

221849820 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

221849820 is an abundant number, since it is smaller than the sum of its proper divisors (468351300).

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

221849820 is a wasteful number, since it uses less digits than its factorization.

221849820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 410851 (or 410843 counting only the distinct ones).

The product of its (nonzero) digits is 18432, while the sum is 36.

The square root of 221849820 is about 14894.6238623203. The cubic root of 221849820 is about 605.3683252244.

The spelling of 221849820 in words is "two hundred twenty-one million, eight hundred forty-nine thousand, eight hundred twenty".