21520423324 has 12 divisors (see below), whose sum is σ = 38875603648. Its totient is φ = 10413108000.

The previous prime is 21520423303. The next prime is 21520423367. The reversal of 21520423324 is 42332402512.

It is a junction number, because it is equal to n+sod(n) for n = 21520423292 and 21520423301.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 86775777 + ... + 86776024.

Almost surely, 2^21520423324 is an apocalyptic number.

It is an amenable number.

21520423324 is a deficient number, since it is larger than the sum of its proper divisors (17355180324).

21520423324 is a wasteful number, since it uses less digits than its factorization.

21520423324 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 173551836 (or 173551834 counting only the distinct ones).

The product of its (nonzero) digits is 11520, while the sum is 28.

Adding to 21520423324 its reverse (42332402512), we get a palindrome (63852825836).

The spelling of 21520423324 in words is "twenty-one billion, five hundred twenty million, four hundred twenty-three thousand, three hundred twenty-four".