21000000001020 has 96 divisors (see below), whose sum is σ = 60056577294336. Its totient is φ = 5480347852800.

The previous prime is 21000000001003. The next prime is 21000000001027. The reversal of 21000000001020 is 2010000000012.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (6).

It is a super Niven number, because it is divisible the sum of any subset of its (nonzero) digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21000000001027) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 30883900 + ... + 31556540.

It is an arithmetic number, because the mean of its divisors is an integer number (625589346816).

Almost surely, 2^{21000000001020} is an apocalyptic number.

21000000001020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21000000001020 is an abundant number, since it is smaller than the sum of its proper divisors (39056577293316).

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

21000000001020 is a wasteful number, since it uses less digits than its factorization.

21000000001020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 683771 (or 683769 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 6.

Adding to 21000000001020 its reverse (2010000000012), we get a palindrome (23010000001032).

The spelling of 21000000001020 in words is "twenty-one trillion, one thousand, twenty".