21221000020020 has 48 divisors (see below), whose sum is σ = 61467724200960. Its totient is φ = 5463797705856.

The previous prime is 21221000020013. The next prime is 21221000020021. The reversal of 21221000020020 is 2002000012212.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a junction number, because it is equal to n+sod(n) for n = 21221000019978 and 21221000020005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21221000020021) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6097986772 + ... + 6097990251.

It is an arithmetic number, because the mean of its divisors is an integer number (1280577587520).

Almost surely, 2^{21221000020020} is an apocalyptic number.

21221000020020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21221000020020 is an abundant number, since it is smaller than the sum of its proper divisors (40246724180940).

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

21221000020020 is a wasteful number, since it uses less digits than its factorization.

21221000020020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12195977064 (or 12195977062 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 12.

Adding to 21221000020020 its reverse (2002000012212), we get a palindrome (23223000032232).

The spelling of 21221000020020 in words is "twenty-one trillion, two hundred twenty-one billion, twenty thousand, twenty".