21323518 has 8 divisors (see below), whose sum is σ = 32060448. Its totient is φ = 10636704.

The previous prime is 21323513. The next prime is 21323521. The reversal of 21323518 is 81532312.

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

It is a junction number, because it is equal to n+sod(n) for n = 21323492 and 21323501.

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 3 ways as a sum of consecutive naturals, for example, 11446 + ... + 13177.

It is an arithmetic number, because the mean of its divisors is an integer number (4007556).

Almost surely, 2^21323518 is an apocalyptic number.

21323518 is a deficient number, since it is larger than the sum of its proper divisors (10736930).

21323518 is a wasteful number, since it uses less digits than its factorization.

21323518 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25058.

The product of its digits is 1440, while the sum is 25.

The square root of 21323518 is about 4617.7394902701. The cubic root of 21323518 is about 277.3019683901.

The spelling of 21323518 in words is "twenty-one million, three hundred twenty-three thousand, five hundred eighteen".