20011021220 has 24 divisors (see below), whose sum is σ = 42025899384. Its totient is φ = 8003883776.

The previous prime is 20011021201. The next prime is 20011021231. The reversal of 20011021220 is 2212011002.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 623800576 + 19387220644 = 24976^2 + 139238^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 462014 + ... + 503466.

It is an arithmetic number, because the mean of its divisors is an integer number (1751079141).

Almost surely, 2^20011021220 is an apocalyptic number.

20011021220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20011021220 is an abundant number, since it is smaller than the sum of its proper divisors (22014878164).

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

20011021220 is a wasteful number, since it uses less digits than its factorization.

20011021220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 65599 (or 65597 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 11.

Adding to 20011021220 its reverse (2212011002), we get a palindrome (22223032222).

The spelling of 20011021220 in words is "twenty billion, eleven million, twenty-one thousand, two hundred twenty".