21421131220 has 24 divisors (see below), whose sum is σ = 45080721504. Its totient is φ = 8550100896.

The previous prime is 21421131191. The next prime is 21421131257. The reversal of 21421131220 is 2213112412.

It is a congruent number.

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, 1137402 + ... + 1156081.

It is an arithmetic number, because the mean of its divisors is an integer number (1878363396).

Almost surely, 2^21421131220 is an apocalyptic number.

21421131220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21421131220 is an abundant number, since it is smaller than the sum of its proper divisors (23659590284).

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

21421131220 is a wasteful number, since it uses less digits than its factorization.

21421131220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2293959 (or 2293957 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 19.

Adding to 21421131220 its reverse (2213112412), we get a palindrome (23634243632).

The spelling of 21421131220 in words is "twenty-one billion, four hundred twenty-one million, one hundred thirty-one thousand, two hundred twenty".