21210220100020 has 96 divisors (see below), whose sum is σ = 51051827473920. Its totient is φ = 7251063114240.

The previous prime is 21210220100009. The next prime is 21210220100021. The reversal of 21210220100020 is 2000102201212.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21210220100021) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 67118946 + ... + 67434214.

It is an arithmetic number, because the mean of its divisors is an integer number (531789869520).

Almost surely, 2^{21210220100020} is an apocalyptic number.

21210220100020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21210220100020 is an abundant number, since it is smaller than the sum of its proper divisors (29841607373900).

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

21210220100020 is a wasteful number, since it uses less digits than its factorization.

21210220100020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 316673 (or 316671 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 13.

Adding to 21210220100020 its reverse (2000102201212), we get a palindrome (23210322301232).

The spelling of 21210220100020 in words is "twenty-one trillion, two hundred ten billion, two hundred twenty million, one hundred thousand, twenty".