21033012020 has 12 divisors (see below), whose sum is σ = 44169325284. Its totient is φ = 8413204800.

The previous prime is 21033012019. The next prime is 21033012023. The reversal of 21033012020 is 2021033012.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 4127291536 + 16905720484 = 64244^2 + 130022^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21033011986 and 21033012004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21033012023) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 525825281 + ... + 525825320.

It is an arithmetic number, because the mean of its divisors is an integer number (3680777107).

Almost surely, 2^21033012020 is an apocalyptic number.

21033012020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21033012020 is an abundant number, since it is smaller than the sum of its proper divisors (23136313264).

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

21033012020 is a wasteful number, since it uses less digits than its factorization.

21033012020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1051650610 (or 1051650608 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 14.

Adding to 21033012020 its reverse (2021033012), we get a palindrome (23054045032).

The spelling of 21033012020 in words is "twenty-one billion, thirty-three million, twelve thousand, twenty".