21004305320 has 16 divisors (see below), whose sum is σ = 47259687060. Its totient is φ = 8401722112.

The previous prime is 21004305293. The next prime is 21004305323. The reversal of 21004305320 is 2350340012.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 18616419364 + 2387885956 = 136442^2 + 48866^2 .

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a junction number, because it is equal to n+sod(n) for n = 21004305292 and 21004305301.

It is not an unprimeable number, because it can be changed into a prime (21004305323) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 262553777 + ... + 262553856.

Almost surely, 2^21004305320 is an apocalyptic number.

21004305320 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21004305320 is an abundant number, since it is smaller than the sum of its proper divisors (26255381740).

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

21004305320 is a wasteful number, since it uses less digits than its factorization.

21004305320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 525107644 (or 525107640 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 20.

Adding to 21004305320 its reverse (2350340012), we get a palindrome (23354645332).

The spelling of 21004305320 in words is "twenty-one billion, four million, three hundred five thousand, three hundred twenty".