21530424420 has 72 divisors (see below), whose sum is σ = 67415712000. Its totient is φ = 5556237120.

The previous prime is 21530424371. The next prime is 21530424437. The reversal of 21530424420 is 2442403512.

21530424420 is a `hidden beast` number, since 215 + 3 + 0 + 4 + 2 + 442 + 0 = 666.

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, 1923670 + ... + 1934829.

Almost surely, 2^21530424420 is an apocalyptic number.

21530424420 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21530424420 is an abundant number, since it is smaller than the sum of its proper divisors (45885287580).

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

21530424420 is a wasteful number, since it uses less digits than its factorization.

21530424420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3858545 (or 3858540 counting only the distinct ones).

The product of its (nonzero) digits is 7680, while the sum is 27.

Adding to 21530424420 its reverse (2442403512), we get a palindrome (23972827932).

The spelling of 21530424420 in words is "twenty-one billion, five hundred thirty million, four hundred twenty-four thousand, four hundred twenty".