21021210320 has 40 divisors (see below), whose sum is σ = 53317435680. Its totient is φ = 7644076160.

The previous prime is 21021210319. The next prime is 21021210349. The reversal of 21021210320 is 2301212012.

It is a happy number.

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

It is a junction number, because it is equal to n+sod(n) for n = 21021210295 and 21021210304.

It is a congruent number.

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, 11942990 + ... + 11944749.

It is an arithmetic number, because the mean of its divisors is an integer number (1332935892).

Almost surely, 2^21021210320 is an apocalyptic number.

21021210320 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21021210320 is an abundant number, since it is smaller than the sum of its proper divisors (32296225360).

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

21021210320 is a wasteful number, since it uses less digits than its factorization.

21021210320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23887763 (or 23887757 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 14.

Adding to 21021210320 its reverse (2301212012), we get a palindrome (23322422332).

The spelling of 21021210320 in words is "twenty-one billion, twenty-one million, two hundred ten thousand, three hundred twenty".