21115220320 has 48 divisors (see below), whose sum is σ = 49913923248. Its totient is φ = 8441141760.

The previous prime is 21115220303. The next prime is 21115220323. The reversal of 21115220320 is 2302251112.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21115220323) 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, 241750 + ... + 317290.

It is an arithmetic number, because the mean of its divisors is an integer number (1039873401).

Almost surely, 2^21115220320 is an apocalyptic number.

21115220320 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21115220320 is an abundant number, since it is smaller than the sum of its proper divisors (28798702928).

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

21115220320 is a wasteful number, since it uses less digits than its factorization.

21115220320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 77303 (or 77295 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 19.

Adding to 21115220320 its reverse (2302251112), we get a palindrome (23417471432).

The spelling of 21115220320 in words is "twenty-one billion, one hundred fifteen million, two hundred twenty thousand, three hundred twenty".