21323947 has 8 divisors (see below), whose sum is σ = 22924800. Its totient is φ = 19770984.

The previous prime is 21323941. The next prime is 21323959. The reversal of 21323947 is 74932312.

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 21323947 - 2¹¹ = 21321899 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21323941) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11047 + ... + 12832.

It is an arithmetic number, because the mean of its divisors is an integer number (2865600).

Almost surely, 2^21323947 is an apocalyptic number.

21323947 is a deficient number, since it is larger than the sum of its proper divisors (1600853).

21323947 is a wasteful number, since it uses less digits than its factorization.

21323947 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23945.

The product of its digits is 9072, while the sum is 31.

The square root of 21323947 is about 4617.7859413360. The cubic root of 21323947 is about 277.3038280230.

The spelling of 21323947 in words is "twenty-one million, three hundred twenty-three thousand, nine hundred forty-seven".