20400221212 has 48 divisors (see below), whose sum is σ = 42266972160. Its totient is φ = 8430710400.

The previous prime is 20400221183. The next prime is 20400221249. The reversal of 20400221212 is 21212200402.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 202089 + ... + 285727.

It is an arithmetic number, because the mean of its divisors is an integer number (880561920).

Almost surely, 2^20400221212 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20400221212, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21133486080).

20400221212 is an abundant number, since it is smaller than the sum of its proper divisors (21866750948).

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

20400221212 is a wasteful number, since it uses less digits than its factorization.

20400221212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 83962 (or 83960 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 16.

Adding to 20400221212 its reverse (21212200402), we get a palindrome (41612421614).

The spelling of 20400221212 in words is "twenty billion, four hundred million, two hundred twenty-one thousand, two hundred twelve".