21624413 has 4 divisors (see below), whose sum is σ = 22762560. Its totient is φ = 20486268.

The previous prime is 21624409. The next prime is 21624443. The reversal of 21624413 is 31442612.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21624413 - 2² = 21624409 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21624443) 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, 569045 + ... + 569082.

It is an arithmetic number, because the mean of its divisors is an integer number (5690640).

Almost surely, 2^21624413 is an apocalyptic number.

It is an amenable number.

21624413 is a deficient number, since it is larger than the sum of its proper divisors (1138147).

21624413 is a wasteful number, since it uses less digits than its factorization.

21624413 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1138146.

The product of its digits is 1152, while the sum is 23.

The square root of 21624413 is about 4650.2056943752. The cubic root of 21624413 is about 278.6002119096.

The spelling of 21624413 in words is "twenty-one million, six hundred twenty-four thousand, four hundred thirteen".