21552323 has 4 divisors (see below), whose sum is σ = 23210208. Its totient is φ = 19894440.

The previous prime is 21552319. The next prime is 21552341. The reversal of 21552323 is 32325512.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21552323 - 2² = 21552319 is a prime.

It is a super-3 number, since 3×21552323³ (a number of 23 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21552353) 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, 828923 + ... + 828948.

It is an arithmetic number, because the mean of its divisors is an integer number (5802552).

Almost surely, 2^21552323 is an apocalyptic number.

21552323 is a deficient number, since it is larger than the sum of its proper divisors (1657885).

21552323 is a wasteful number, since it uses less digits than its factorization.

21552323 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1657884.

The product of its digits is 1800, while the sum is 23.

The square root of 21552323 is about 4642.4479533970. The cubic root of 21552323 is about 278.2902744136.

Adding to 21552323 its reverse (32325512), we get a palindrome (53877835).

The spelling of 21552323 in words is "twenty-one million, five hundred fifty-two thousand, three hundred twenty-three".