21000022002 has 24 divisors (see below), whose sum is σ = 45572180160. Its totient is φ = 6988910040.

The previous prime is 21000021907. The next prime is 21000022007. The reversal of 21000022002 is 20022000012.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is not an unprimeable number, because it can be changed into a prime (21000022007) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 913102 + ... + 935817.

It is an arithmetic number, because the mean of its divisors is an integer number (1898840840).

Almost surely, 2^21000022002 is an apocalyptic number.

21000022002 is an abundant number, since it is smaller than the sum of its proper divisors (24572158158).

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

21000022002 is a wasteful number, since it uses less digits than its factorization.

21000022002 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1849558 (or 1849555 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 9.

Adding to 21000022002 its reverse (20022000012), we get a palindrome (41022022014).

The spelling of 21000022002 in words is "twenty-one billion, twenty-two thousand, two".