21031102020 has 48 divisors (see below), whose sum is σ = 61447397760. Its totient is φ = 5364454656.

The previous prime is 21031102019. The next prime is 21031102021. The reversal of 21031102020 is 2020113012.

It is an interprime number because it is at equal distance from previous prime (21031102019) and next prime (21031102021).

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a junction number, because it is equal to n+sod(n) for n = 21031101987 and 21031102005.

It is not an unprimeable number, because it can be changed into a prime (21031102021) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7618585 + ... + 7621344.

It is an arithmetic number, because the mean of its divisors is an integer number (1280154120).

Almost surely, 2^21031102020 is an apocalyptic number.

21031102020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21031102020 is an abundant number, since it is smaller than the sum of its proper divisors (40416295740).

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

21031102020 is a wasteful number, since it uses less digits than its factorization.

21031102020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15239964 (or 15239962 counting only the distinct ones).

The product of its (nonzero) digits is 24, while the sum is 12.

Adding to 21031102020 its reverse (2020113012), we get a palindrome (23051215032).

The spelling of 21031102020 in words is "twenty-one billion, thirty-one million, one hundred two thousand, twenty".