21020221000 has 64 divisors (see below), whose sum is σ = 49674558960. Its totient is φ = 8324800000.

The previous prime is 21020220967. The next prime is 21020221031. The reversal of 21020221000 is 12202012.

It can be written as a sum of positive squares in 8 ways, for example, as 988347844 + 20031873156 = 31438^2 + 141534^2 .

It is a super-3 number, since 3×21020221000³ (a number of 32 digits) contains 333 as substring.

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

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 3061 + ... + 205060.

Almost surely, 2^21020221000 is an apocalyptic number.

21020221000 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21020221000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24837279480).

21020221000 is an abundant number, since it is smaller than the sum of its proper divisors (28654337960).

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

21020221000 is a wasteful number, since it uses less digits than its factorization.

21020221000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 208243 (or 208229 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 10.

Adding to 21020221000 its reverse (12202012), we get a palindrome (21032423012).

The spelling of 21020221000 in words is "twenty-one billion, twenty million, two hundred twenty-one thousand".