21020011221220 has 24 divisors (see below), whose sum is σ = 48154934798208. Its totient is φ = 7643640444000.

The previous prime is 21020011221173. The next prime is 21020011221227. The reversal of 21020011221220 is 2212211002012.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 21020011221194 and 21020011221203.

It is not an unprimeable number, because it can be changed into a prime (21020011221227) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 47772752556 + ... + 47772752995.

It is an arithmetic number, because the mean of its divisors is an integer number (2006455616592).

Almost surely, 2^{21020011221220} is an apocalyptic number.

21020011221220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21020011221220 is an abundant number, since it is smaller than the sum of its proper divisors (27134923576988).

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

21020011221220 is a wasteful number, since it uses less digits than its factorization.

21020011221220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 95545505571 (or 95545505569 counting only the distinct ones).

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

Adding to 21020011221220 its reverse (2212211002012), we get a palindrome (23232222223232).

The spelling of 21020011221220 in words is "twenty-one trillion, twenty billion, eleven million, two hundred twenty-one thousand, two hundred twenty".