21004445320 has 32 divisors (see below), whose sum is σ = 47275018200. Its totient is φ = 8399108608.

The previous prime is 21004445239. The next prime is 21004445321. The reversal of 21004445320 is 2354440012.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 18630612036 + 2373833284 = 136494^2 + 48722^2 .

It is not an unprimeable number, because it can be changed into a prime (21004445321) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 46542 + ... + 210178.

Almost surely, 2^21004445320 is an apocalyptic number.

21004445320 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21004445320 is an abundant number, since it is smaller than the sum of its proper divisors (26270572880).

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

21004445320 is a wasteful number, since it uses less digits than its factorization.

21004445320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 166857 (or 166853 counting only the distinct ones).

The product of its (nonzero) digits is 3840, while the sum is 25.

Adding to 21004445320 its reverse (2354440012), we get a palindrome (23358885332).

The spelling of 21004445320 in words is "twenty-one billion, four million, four hundred forty-five thousand, three hundred twenty".