21012002320 has 40 divisors (see below), whose sum is σ = 48859294680. Its totient is φ = 8403701760.

The previous prime is 21012002303. The next prime is 21012002339. The reversal of 21012002320 is 2320021012.

It can be written as a sum of positive squares in 4 ways, for example, as 3849954304 + 17162048016 = 62048^2 + 131004^2 .

It is a tau number, because it is divible by the number of its divisors (40).

It is a self number, because there is not a number n which added to its sum of digits gives 21012002320.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 907690 + ... + 930550.

It is an arithmetic number, because the mean of its divisors is an integer number (1221482367).

Almost surely, 2^21012002320 is an apocalyptic number.

21012002320 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21012002320 is an abundant number, since it is smaller than the sum of its proper divisors (27847292360).

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

21012002320 is a wasteful number, since it uses less digits than its factorization.

21012002320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34363 (or 34357 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 13.

Adding to 21012002320 its reverse (2320021012), we get a palindrome (23332023332).

The spelling of 21012002320 in words is "twenty-one billion, twelve million, two thousand, three hundred twenty".