21213210320 has 20 divisors (see below), whose sum is σ = 49320714180. Its totient is φ = 8485284096.

The previous prime is 21213210251. The next prime is 21213210331. The reversal of 21213210320 is 2301231212.

It can be written as a sum of positive squares in 2 ways, for example, as 15469389376 + 5743820944 = 124376^2 + 75788^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 132582485 + ... + 132582644.

It is an arithmetic number, because the mean of its divisors is an integer number (2466035709).

Almost surely, 2^21213210320 is an apocalyptic number.

21213210320 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21213210320 is an abundant number, since it is smaller than the sum of its proper divisors (28107503860).

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

21213210320 is a wasteful number, since it uses less digits than its factorization.

21213210320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 265165142 (or 265165136 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 17.

Adding to 21213210320 its reverse (2301231212), we get a palindrome (23514441532).

The spelling of 21213210320 in words is "twenty-one billion, two hundred thirteen million, two hundred ten thousand, three hundred twenty".