21204030420 has 96 divisors (see below), whose sum is σ = 66000291840. Its totient is φ = 5651648640.

The previous prime is 21204030409. The next prime is 21204030433. The reversal of 21204030420 is 2403040212.

21204030420 is a `hidden beast` number, since 212 + 0 + 4 + 0 + 30 + 420 = 666.

It is a super-2 number, since 2×21204030420² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 21204030393 and 21204030402.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1251405 + ... + 1268235.

It is an arithmetic number, because the mean of its divisors is an integer number (687503040).

Almost surely, 2^21204030420 is an apocalyptic number.

21204030420 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21204030420 is an abundant number, since it is smaller than the sum of its proper divisors (44796261420).

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

21204030420 is a wasteful number, since it uses less digits than its factorization.

21204030420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19182 (or 19174 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 18.

Adding to 21204030420 its reverse (2403040212), we get a palindrome (23607070632).

The spelling of 21204030420 in words is "twenty-one billion, two hundred four million, thirty thousand, four hundred twenty".