221221000020 has 48 divisors (see below), whose sum is σ = 620040250368. Its totient is φ = 58933080960.

The previous prime is 221221000009. The next prime is 221221000037. The reversal of 221221000020 is 20000122122.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a congruent number.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 1789236 + ... + 1908875.

It is an arithmetic number, because the mean of its divisors is an integer number (12917505216).

Almost surely, 2^221221000020 is an apocalyptic number.

221221000020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

221221000020 is an abundant number, since it is smaller than the sum of its proper divisors (398819250348).

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

221221000020 is a wasteful number, since it uses less digits than its factorization.

221221000020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3699120 (or 3699118 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 12.

Adding to 221221000020 its reverse (20000122122), we get a palindrome (241221122142).

The spelling of 221221000020 in words is "two hundred twenty-one billion, two hundred twenty-one million, twenty", and thus it is an aban number.