221221212020 has 12 divisors (see below), whose sum is σ = 464564545284. Its totient is φ = 88488484800.

The previous prime is 221221212019. The next prime is 221221212083. The reversal of 221221212020 is 20212122122.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 31942268176 + 189278943844 = 178724^2 + 435062^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 221221212020.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5530530281 + ... + 5530530320.

It is an arithmetic number, because the mean of its divisors is an integer number (38713712107).

Almost surely, 2^221221212020 is an apocalyptic number.

221221212020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

221221212020 is an abundant number, since it is smaller than the sum of its proper divisors (243343333264).

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

221221212020 is a wasteful number, since it uses less digits than its factorization.

221221212020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11061060610 (or 11061060608 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 17.

Adding to 221221212020 its reverse (20212122122), we get a palindrome (241433334142).

The spelling of 221221212020 in words is "two hundred twenty-one billion, two hundred twenty-one million, two hundred twelve thousand, twenty".