21623613 has 8 divisors (see below), whose sum is σ = 31452576. Its totient is φ = 13105200.

The previous prime is 21623603. The next prime is 21623617. The reversal of 21623613 is 31632612.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21623613 - 2⁹ = 21623101 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21623617) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 327598 + ... + 327663.

It is an arithmetic number, because the mean of its divisors is an integer number (3931572).

Almost surely, 2^21623613 is an apocalyptic number.

It is an amenable number.

21623613 is a deficient number, since it is larger than the sum of its proper divisors (9828963).

21623613 is a wasteful number, since it uses less digits than its factorization.

21623613 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 655275.

The product of its digits is 1296, while the sum is 24.

The square root of 21623613 is about 4650.1196758793. The cubic root of 21623613 is about 278.5967762415.

It can be divided in two parts, 2162 and 3613, that added together give a palindrome (5775).

The spelling of 21623613 in words is "twenty-one million, six hundred twenty-three thousand, six hundred thirteen".