21020020100 has 36 divisors (see below), whose sum is σ = 45795225168. Its totient is φ = 8374500000.

The previous prime is 21020020069. The next prime is 21020020103. The reversal of 21020020100 is 102002012.

It is not an unprimeable number, because it can be changed into a prime (21020020103) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 393626 + ... + 443825.

It is an arithmetic number, because the mean of its divisors is an integer number (1272089588).

Almost surely, 2^21020020100 is an apocalyptic number.

21020020100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21020020100 is an abundant number, since it is smaller than the sum of its proper divisors (24775205068).

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

21020020100 is a wasteful number, since it uses less digits than its factorization.

21020020100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 837716 (or 837709 counting only the distinct ones).

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

Adding to 21020020100 its reverse (102002012), we get a palindrome (21122022112).

The spelling of 21020020100 in words is "twenty-one billion, twenty million, twenty thousand, one hundred".