21012010320 has 320 divisors, whose sum is σ = 81066240000. Its totient is φ = 4392880128.

The previous prime is 21012010259. The next prime is 21012010361. The reversal of 21012010320 is 2301021012.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a junction number, because it is equal to n+sod(n) for n = 21012010296 and 21012010305.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 914331 + ... + 937029.

It is an arithmetic number, because the mean of its divisors is an integer number (253332000).

Almost surely, 2^21012010320 is an apocalyptic number.

21012010320 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 21012010320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40533120000).

21012010320 is an abundant number, since it is smaller than the sum of its proper divisors (60054229680).

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

21012010320 is a wasteful number, since it uses less digits than its factorization.

21012010320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22770 (or 22764 counting only the distinct ones).

The product of its (nonzero) digits is 24, while the sum is 12.

Adding to 21012010320 its reverse (2301021012), we get a palindrome (23313031332).

The spelling of 21012010320 in words is "twenty-one billion, twelve million, ten thousand, three hundred twenty".