21202221121020 has 72 divisors (see below), whose sum is σ = 64313871017760. Its totient is φ = 5653884581760.

The previous prime is 21202221120959. The next prime is 21202221121051. The reversal of 21202221121020 is 2012112220212.

It is a happy number.

21202221121020 is a `hidden beast` number, since 21 + 202 + 2 + 211 + 210 + 20 = 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 = 21202221120984 and 21202221121002.

It is a congruent number.

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, 30716041 + ... + 31398719.

It is an arithmetic number, because the mean of its divisors is an integer number (893248208580).

Almost surely, 2^{21202221121020} is an apocalyptic number.

21202221121020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21202221121020 is an abundant number, since it is smaller than the sum of its proper divisors (43111649896740).

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

21202221121020 is a wasteful number, since it uses less digits than its factorization.

21202221121020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 855235 (or 855230 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 18.

Adding to 21202221121020 its reverse (2012112220212), we get a palindrome (23214333341232).

The spelling of 21202221121020 in words is "twenty-one trillion, two hundred two billion, two hundred twenty-one million, one hundred twenty-one thousand, twenty".