21108306420 has 72 divisors (see below), whose sum is σ = 64073449440. Its totient is φ = 5624932800.

The previous prime is 21108306391. The next prime is 21108306467. The reversal of 21108306420 is 2460380112.

21108306420 is a `hidden beast` number, since 2 + 1 + 10 + 8 + 3 + 0 + 642 + 0 = 666.

It is a super-2 number, since 2×21108306420² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 220771 + ... + 301589.

It is an arithmetic number, because the mean of its divisors is an integer number (889909020).

Almost surely, 2^21108306420 is an apocalyptic number.

21108306420 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21108306420 is an abundant number, since it is smaller than the sum of its proper divisors (42965143020).

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

21108306420 is a wasteful number, since it uses less digits than its factorization.

21108306420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 82285 (or 82280 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 27.

Adding to 21108306420 its reverse (2460380112), we get a palindrome (23568686532).

The spelling of 21108306420 in words is "twenty-one billion, one hundred eight million, three hundred six thousand, four hundred twenty".