21130624 has 16 divisors (see below), whose sum is σ = 42096420. Its totient is φ = 10565248.

The previous prime is 21130619. The next prime is 21130649. The reversal of 21130624 is 42603112.

It is a tau number, because it is divible by the number of its divisors (16).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82414 + ... + 82669.

Almost surely, 2^21130624 is an apocalyptic number.

It is an amenable number.

21130624 is a deficient number, since it is larger than the sum of its proper divisors (20965796).

21130624 is an equidigital number, since it uses as much as digits as its factorization.

21130624 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 165097 (or 165085 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 19.

The square root of 21130624 is about 4596.8058475424. The cubic root of 21130624 is about 276.4632701282.

Adding to 21130624 its reverse (42603112), we get a palindrome (63733736).

The spelling of 21130624 in words is "twenty-one million, one hundred thirty thousand, six hundred twenty-four".