21121305320 has 32 divisors (see below), whose sum is σ = 47607397920. Its totient is φ = 8433506880.

The previous prime is 21121305319. The next prime is 21121305341. The reversal of 21121305320 is 2350312112.

It is a super-2 number, since 2×21121305320² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a junction number, because it is equal to n+sod(n) for n = 21121305292 and 21121305301.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 446426 + ... + 491465.

It is an arithmetic number, because the mean of its divisors is an integer number (1487731185).

Almost surely, 2^21121305320 is an apocalyptic number.

21121305320 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21121305320 is an abundant number, since it is smaller than the sum of its proper divisors (26486092600).

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

21121305320 is a wasteful number, since it uses less digits than its factorization.

21121305320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 938465 (or 938461 counting only the distinct ones).

The product of its (nonzero) digits is 360, while the sum is 20.

Adding to 21121305320 its reverse (2350312112), we get a palindrome (23471617432).

The spelling of 21121305320 in words is "twenty-one billion, one hundred twenty-one million, three hundred five thousand, three hundred twenty".