20021000001000 has 256 divisors, whose sum is σ = 64049571106560. Its totient is φ = 5204827929600.

The previous prime is 20021000000873. The next prime is 20021000001073. The reversal of 20021000001000 is 10000012002.

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 self number, because there is not a number n which added to its sum of digits gives 20021000001000.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 24561987 + ... + 25364013.

It is an arithmetic number, because the mean of its divisors is an integer number (250193637135).

Almost surely, 2^{20021000001000} is an apocalyptic number.

20021000001000 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 20021000001000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32024785553280).

20021000001000 is an abundant number, since it is smaller than the sum of its proper divisors (44028571105560).

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

20021000001000 is a wasteful number, since it uses less digits than its factorization.

20021000001000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 802261 (or 802247 counting only the distinct ones).

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

Adding to 20021000001000 its reverse (10000012002), we get a palindrome (20031000013002).

The spelling of 20021000001000 in words is "twenty trillion, twenty-one billion, one thousand".