20321321620 has 96 divisors (see below), whose sum is σ = 46707010560. Its totient is φ = 7396976640.

The previous prime is 20321321611. The next prime is 20321321621. The reversal of 20321321620 is 2612312302.

It is a super-2 number, since 2×20321321620² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 20321321591 and 20321321600.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20321321621) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1215357 + ... + 1231963.

It is an arithmetic number, because the mean of its divisors is an integer number (486531360).

Almost surely, 2^20321321620 is an apocalyptic number.

20321321620 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 20321321620, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23353505280).

20321321620 is an abundant number, since it is smaller than the sum of its proper divisors (26385688940).

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

20321321620 is a wasteful number, since it uses less digits than its factorization.

20321321620 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16753 (or 16751 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 22.

Adding to 20321321620 its reverse (2612312302), we get a palindrome (22933633922).

The spelling of 20321321620 in words is "twenty billion, three hundred twenty-one million, three hundred twenty-one thousand, six hundred twenty".