21620324 has 12 divisors (see below), whose sum is σ = 41275248. Its totient is φ = 9827400.

The previous prime is 21620323. The next prime is 21620359. The reversal of 21620324 is 42302612.

It is a junction number, because it is equal to n+sod(n) for n = 21620296 and 21620305.

It is not an unprimeable number, because it can be changed into a prime (21620323) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 245642 + ... + 245729.

It is an arithmetic number, because the mean of its divisors is an integer number (3439604).

Almost surely, 2^21620324 is an apocalyptic number.

It is an amenable number.

21620324 is a deficient number, since it is larger than the sum of its proper divisors (19654924).

21620324 is a wasteful number, since it uses less digits than its factorization.

21620324 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 491386 (or 491384 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 20.

The square root of 21620324 is about 4649.7660156184. The cubic root of 21620324 is about 278.5826504606.

Adding to 21620324 its reverse (42302612), we get a palindrome (63922936).

The spelling of 21620324 in words is "twenty-one million, six hundred twenty thousand, three hundred twenty-four".