21002102000 has 80 divisors (see below), whose sum is σ = 55399784544. Its totient is φ = 7637120000.

The previous prime is 21002101993. The next prime is 21002102021. The reversal of 21002102000 is 20120012.

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (8).

It is a congruent number.

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, 455321 + ... + 499320.

Almost surely, 2^21002102000 is an apocalyptic number.

21002102000 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21002102000 is an abundant number, since it is smaller than the sum of its proper divisors (34397682544).

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

21002102000 is a wasteful number, since it uses less digits than its factorization.

21002102000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 954675 (or 954659 counting only the distinct ones).

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

Adding to 21002102000 its reverse (20120012), we get a palindrome (21022222012).

The spelling of 21002102000 in words is "twenty-one billion, two million, one hundred two thousand".