21402312320 has 128 divisors (see below), whose sum is σ = 52032240000. Its totient is φ = 8417046528.

The previous prime is 21402312317. The next prime is 21402312361. The reversal of 21402312320 is 2321320412.

It is a tau number, because it is divible by the number of its divisors (128).

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 = 21402312292 and 21402312301.

It is an unprimeable number.

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, 9820991 + ... + 9823169.

It is an arithmetic number, because the mean of its divisors is an integer number (406501875).

Almost surely, 2^21402312320 is an apocalyptic number.

21402312320 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21402312320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26016120000).

21402312320 is an abundant number, since it is smaller than the sum of its proper divisors (30629927680).

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

21402312320 is a wasteful number, since it uses less digits than its factorization.

21402312320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2450 (or 2438 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 20.

Adding to 21402312320 its reverse (2321320412), we get a palindrome (23723632732).

The spelling of 21402312320 in words is "twenty-one billion, four hundred two million, three hundred twelve thousand, three hundred twenty".