21323507 has 8 divisors (see below), whose sum is σ = 22852896. Its totient is φ = 19844352.

The previous prime is 21323503. The next prime is 21323509. The reversal of 21323507 is 70532312.

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

It is a cyclic number.

It is not a de Polignac number, because 21323507 - 2² = 21323503 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (23).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21323503) 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, 11678 + ... + 13379.

It is an arithmetic number, because the mean of its divisors is an integer number (2856612).

Almost surely, 2^21323507 is an apocalyptic number.

21323507 is a deficient number, since it is larger than the sum of its proper divisors (1529389).

21323507 is a wasteful number, since it uses less digits than its factorization.

21323507 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25117.

The product of its (nonzero) digits is 1260, while the sum is 23.

The square root of 21323507 is about 4617.7382992110. The cubic root of 21323507 is about 277.3019207069.

Adding to 21323507 its reverse (70532312), we get a palindrome (91855819).

The spelling of 21323507 in words is "twenty-one million, three hundred twenty-three thousand, five hundred seven".