21110002020 has 72 divisors (see below), whose sum is σ = 64239739200. Its totient is φ = 5611218240.

The previous prime is 21110001949. The next prime is 21110002051. The reversal of 21110002020 is 2020001112.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a junction number, because it is equal to n+sod(n) for n = 21110001993 and 21110002011.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 132570 + ... + 244529.

It is an arithmetic number, because the mean of its divisors is an integer number (892218600).

Almost surely, 2^21110002020 is an apocalyptic number.

21110002020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21110002020 is an abundant number, since it is smaller than the sum of its proper divisors (43129737180).

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

21110002020 is a wasteful number, since it uses less digits than its factorization.

21110002020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 377425 (or 377420 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 9.

Adding to 21110002020 its reverse (2020001112), we get a palindrome (23130003132).

The spelling of 21110002020 in words is "twenty-one billion, one hundred ten million, two thousand, twenty".