21323517 has 8 divisors (see below), whose sum is σ = 28453920. Its totient is φ = 14204400.

The previous prime is 21323513. The next prime is 21323521. The reversal of 21323517 is 71532312.

It is an interprime number because it is at equal distance from previous prime (21323513) and next prime (21323521).

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

It is not a de Polignac number, because 21323517 - 2² = 21323513 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21323513) 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, 3834 + ... + 7572.

It is an arithmetic number, because the mean of its divisors is an integer number (3556740).

Almost surely, 2^21323517 is an apocalyptic number.

It is an amenable number.

21323517 is a deficient number, since it is larger than the sum of its proper divisors (7130403).

21323517 is a wasteful number, since it uses less digits than its factorization.

21323517 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5643.

The product of its digits is 1260, while the sum is 24.

The square root of 21323517 is about 4617.7393819920. The cubic root of 21323517 is about 277.3019640552.

Adding to 21323517 its reverse (71532312), we get a palindrome (92855829).

The spelling of 21323517 in words is "twenty-one million, three hundred twenty-three thousand, five hundred seventeen".