21033101820 has 24 divisors (see below), whose sum is σ = 58892685264. Its totient is φ = 5608827136.

The previous prime is 21033101819. The next prime is 21033101839. The reversal of 21033101820 is 2810133012.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 175275789 + ... + 175275908.

It is an arithmetic number, because the mean of its divisors is an integer number (2453861886).

Almost surely, 2^21033101820 is an apocalyptic number.

21033101820 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21033101820 is an abundant number, since it is smaller than the sum of its proper divisors (37859583444).

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

21033101820 is a wasteful number, since it uses less digits than its factorization.

21033101820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 350551709 (or 350551707 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 21.

Adding to 21033101820 its reverse (2810133012), we get a palindrome (23843234832).

The spelling of 21033101820 in words is "twenty-one billion, thirty-three million, one hundred one thousand, eight hundred twenty".