21021001020100 has 216 divisors, whose sum is σ = 48298252713984. Its totient is φ = 7932443904000.

The previous prime is 21021001019999. The next prime is 21021001020109. The reversal of 21021001020100 is 102010012012.

It is a Harshad number since it is a multiple of its sum of digits (10).

It is not an unprimeable number, because it can be changed into a prime (21021001020109) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 1303458237 + ... + 1303474363.

It is an arithmetic number, because the mean of its divisors is an integer number (223603021824).

Almost surely, 2^{21021001020100} is an apocalyptic number.

21021001020100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21021001020100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24149126356992).

21021001020100 is an abundant number, since it is smaller than the sum of its proper divisors (27277251693884).

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

21021001020100 is a wasteful number, since it uses less digits than its factorization.

21021001020100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16407 (or 16339 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 10.

Adding to 21021001020100 its reverse (102010012012), we get a palindrome (21123011032112).

The spelling of 21021001020100 in words is "twenty-one trillion, twenty-one billion, one million, twenty thousand, one hundred".