21421301220 has 72 divisors (see below), whose sum is σ = 70885039680. Its totient is φ = 5193042240.

The previous prime is 21421301207. The next prime is 21421301243. The reversal of 21421301220 is 2210312412.

It is a happy number.

21421301220 is a `hidden beast` number, since 2 + 142 + 1 + 301 + 220 = 666.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 21421301193 and 21421301202.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 5407440 + ... + 5411399.

It is an arithmetic number, because the mean of its divisors is an integer number (984514440).

Almost surely, 2^21421301220 is an apocalyptic number.

21421301220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21421301220 is an abundant number, since it is smaller than the sum of its proper divisors (49463738460).

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

21421301220 is a wasteful number, since it uses less digits than its factorization.

21421301220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10818865 (or 10818860 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

Adding to 21421301220 its reverse (2210312412), we get a palindrome (23631613632).

The spelling of 21421301220 in words is "twenty-one billion, four hundred twenty-one million, three hundred one thousand, two hundred twenty".