21200001020 has 36 divisors (see below), whose sum is σ = 48935214552. Its totient is φ = 7709090400.

The previous prime is 21200001019. The next prime is 21200001041. The reversal of 21200001020 is 2010000212.

It is a junction number, because it is equal to n+sod(n) for n = 21200000989 and 21200001007.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 4377746 + ... + 4382585.

Almost surely, 2^21200001020 is an apocalyptic number.

21200001020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21200001020 is an abundant number, since it is smaller than the sum of its proper divisors (27735213532).

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

21200001020 is a wasteful number, since it uses less digits than its factorization.

21200001020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8760362 (or 8760349 counting only the distinct ones).

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

Adding to 21200001020 its reverse (2010000212), we get a palindrome (23210001232).

The spelling of 21200001020 in words is "twenty-one billion, two hundred million, one thousand, twenty".