21320444430 has 128 divisors (see below), whose sum is σ = 60762908160. Its totient is φ = 5300881920.

The previous prime is 21320444423. The next prime is 21320444443. The reversal of 21320444430 is 3444402312.

It is a happy number.

21320444430 is a `hidden beast` number, since 2 + 13 + 204 + 4 + 443 + 0 = 666.

It is a super-2 number, since 2×21320444430² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a junction number, because it is equal to n+sod(n) for n = 21320444394 and 21320444403.

It is a congruent number.

It is an unprimeable number.

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 63 ways as a sum of consecutive naturals, for example, 469425 + ... + 512835.

It is an arithmetic number, because the mean of its divisors is an integer number (474710220).

Almost surely, 2^21320444430 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21320444430, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30381454080).

21320444430 is an abundant number, since it is smaller than the sum of its proper divisors (39442463730).

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

21320444430 is a wasteful number, since it uses less digits than its factorization.

21320444430 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43551 (or 43545 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 27.

Adding to 21320444430 its reverse (3444402312), we get a palindrome (24764846742).

The spelling of 21320444430 in words is "twenty-one billion, three hundred twenty million, four hundred forty-four thousand, four hundred thirty".