21213021320 has 32 divisors (see below), whose sum is σ = 47751064920. Its totient is φ = 8481338880.

The previous prime is 21213021307. The next prime is 21213021329. The reversal of 21213021320 is 2312031212.

It can be written as a sum of positive squares in 4 ways, for example, as 20735424004 + 477597316 = 143998^2 + 21854^2 .

It is a super-3 number, since 3×21213021320³ (a number of 32 digits) contains 333 as substring.

It is not an unprimeable number, because it can be changed into a prime (21213021329) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 31301 + ... + 208340.

Almost surely, 2^21213021320 is an apocalyptic number.

21213021320 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21213021320 is an abundant number, since it is smaller than the sum of its proper divisors (26538043600).

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

21213021320 is a wasteful number, since it uses less digits than its factorization.

21213021320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 241865 (or 241861 counting only the distinct ones).

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

Adding to 21213021320 its reverse (2312031212), we get a palindrome (23525052532).

The spelling of 21213021320 in words is "twenty-one billion, two hundred thirteen million, twenty-one thousand, three hundred twenty".