21323687 has 16 divisors (see below), whose sum is σ = 26687232. Its totient is φ = 16552320.

The previous prime is 21323669. The next prime is 21323689. The reversal of 21323687 is 78632312.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 21323687 - 2¹⁶ = 21258151 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21323689) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 35663 + ... + 36255.

It is an arithmetic number, because the mean of its divisors is an integer number (1667952).

Almost surely, 2^21323687 is an apocalyptic number.

21323687 is a deficient number, since it is larger than the sum of its proper divisors (5363545).

21323687 is a wasteful number, since it uses less digits than its factorization.

21323687 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1078.

The product of its digits is 12096, while the sum is 32.

The square root of 21323687 is about 4617.7577892306. The cubic root of 21323687 is about 277.3027009757.

Adding to 21323687 its reverse (78632312), we get a palindrome (99955999).

The spelling of 21323687 in words is "twenty-one million, three hundred twenty-three thousand, six hundred eighty-seven".