20000021220 has 72 divisors (see below), whose sum is σ = 63304428096. Its totient is φ = 5101453632.

The previous prime is 20000021203. The next prime is 20000021221. The reversal of 20000021220 is 2212000002.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is not an unprimeable number, because it can be changed into a prime (20000021221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2411322 + ... + 2419601.

It is an arithmetic number, because the mean of its divisors is an integer number (879228168).

Almost surely, 2^20000021220 is an apocalyptic number.

20000021220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20000021220 is an abundant number, since it is smaller than the sum of its proper divisors (43304406876).

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

20000021220 is a wasteful number, since it uses less digits than its factorization.

20000021220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4830961 (or 4830956 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 9.

Adding to 20000021220 its reverse (2212000002), we get a palindrome (22212021222).

The spelling of 20000021220 in words is "twenty billion, twenty-one thousand, two hundred twenty".