21011102020 has 12 divisors (see below), whose sum is σ = 44123314284. Its totient is φ = 8404440800.

The previous prime is 21011102017. The next prime is 21011102027. The reversal of 21011102020 is 2020111012.

It can be written as a sum of positive squares in 2 ways, for example, as 2999314756 + 18011787264 = 54766^2 + 134208^2 .

It is a Harshad number since it is a multiple of its sum of digits (10).

It is a junction number, because it is equal to n+sod(n) for n = 21011101988 and 21011102006.

It is not an unprimeable number, because it can be changed into a prime (21011102027) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 525277531 + ... + 525277570.

It is an arithmetic number, because the mean of its divisors is an integer number (3676942857).

Almost surely, 2^21011102020 is an apocalyptic number.

21011102020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21011102020 is an abundant number, since it is smaller than the sum of its proper divisors (23112212264).

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

21011102020 is a wasteful number, since it uses less digits than its factorization.

21011102020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1050555110 (or 1050555108 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 10.

Adding to 21011102020 its reverse (2020111012), we get a palindrome (23031213032).

The spelling of 21011102020 in words is "twenty-one billion, eleven million, one hundred two thousand, twenty".