21764002000 has 80 divisors (see below), whose sum is σ = 56673528912. Its totient is φ = 8035929600.

The previous prime is 21764001989. The next prime is 21764002009. The reversal of 21764002000 is 20046712.

It can be written as a sum of positive squares in 8 ways, for example, as 4168510096 + 17595491904 = 64564^2 + 132648^2 .

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21764002009) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 392539 + ... + 444538.

Almost surely, 2^21764002000 is an apocalyptic number.

21764002000 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21764002000 is an abundant number, since it is smaller than the sum of its proper divisors (34909526912).

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

21764002000 is a wasteful number, since it uses less digits than its factorization.

21764002000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 837113 (or 837097 counting only the distinct ones).

The product of its (nonzero) digits is 672, while the sum is 22.

Adding to 21764002000 its reverse (20046712), we get a palindrome (21784048712).

The spelling of 21764002000 in words is "twenty-one billion, seven hundred sixty-four million, two thousand".