21421211020 has 24 divisors (see below), whose sum is σ = 49074047568. Its totient is φ = 7789531200.

The previous prime is 21421211003. The next prime is 21421211039. The reversal of 21421211020 is 2011212412.

It is a junction number, because it is equal to n+sod(n) for n = 21421210985 and 21421211003.

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, 48684351 + ... + 48684790.

It is an arithmetic number, because the mean of its divisors is an integer number (2044751982).

Almost surely, 2^21421211020 is an apocalyptic number.

21421211020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21421211020 is an abundant number, since it is smaller than the sum of its proper divisors (27652836548).

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

21421211020 is a wasteful number, since it uses less digits than its factorization.

21421211020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 97369161 (or 97369159 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 16.

Adding to 21421211020 its reverse (2011212412), we get a palindrome (23432423432).

The spelling of 21421211020 in words is "twenty-one billion, four hundred twenty-one million, two hundred eleven thousand, twenty".