21315335220 has 48 divisors (see below), whose sum is σ = 66314377920. Its totient is φ = 5684089248.

The previous prime is 21315335207. The next prime is 21315335263. The reversal of 21315335220 is 2253351312.

It is a happy number.

21315335220 is a `hidden beast` number, since 2 + 131 + 5 + 3 + 3 + 522 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

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 15 ways as a sum of consecutive naturals, for example, 19735882 + ... + 19736961.

It is an arithmetic number, because the mean of its divisors is an integer number (1381549540).

Almost surely, 2^21315335220 is an apocalyptic number.

21315335220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21315335220 is an abundant number, since it is smaller than the sum of its proper divisors (44999042700).

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

21315335220 is a wasteful number, since it uses less digits than its factorization.

21315335220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39472861 (or 39472853 counting only the distinct ones).

The product of its (nonzero) digits is 5400, while the sum is 27.

Adding to 21315335220 its reverse (2253351312), we get a palindrome (23568686532).

The spelling of 21315335220 in words is "twenty-one billion, three hundred fifteen million, three hundred thirty-five thousand, two hundred twenty".