21120002000 has 80 divisors (see below), whose sum is σ = 52313932944. Its totient is φ = 8241920000.

The previous prime is 21120001927. The next prime is 21120002009. The reversal of 21120002000 is 20002112.

It can be written as a sum of positive squares in 8 ways, for example, as 14885952064 + 6234049936 = 122008^2 + 78956^2 .

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 not an unprimeable number, because it can be changed into a prime (21120002009) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 46781 + ... + 210780.

Almost surely, 2^21120002000 is an apocalyptic number.

21120002000 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21120002000 is an abundant number, since it is smaller than the sum of its proper divisors (31193930944).

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

21120002000 is a wasteful number, since it uses less digits than its factorization.

21120002000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 257625 (or 257609 counting only the distinct ones).

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

Adding to 21120002000 its reverse (20002112), we get a palindrome (21140004112).

The spelling of 21120002000 in words is "twenty-one billion, one hundred twenty million, two thousand".