21323455 has 4 divisors (see below), whose sum is σ = 25588152. Its totient is φ = 17058760.

The previous prime is 21323441. The next prime is 21323473. The reversal of 21323455 is 55432312.

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

It is not a de Polignac number, because 21323455 - 2¹¹ = 21321407 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2132341 + ... + 2132350.

It is an arithmetic number, because the mean of its divisors is an integer number (6397038).

Almost surely, 2^21323455 is an apocalyptic number.

21323455 is a deficient number, since it is larger than the sum of its proper divisors (4264697).

21323455 is an equidigital number, since it uses as much as digits as its factorization.

21323455 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4264696.

The product of its digits is 3600, while the sum is 25.

The square root of 21323455 is about 4617.7326687456. The cubic root of 21323455 is about 277.3016952950.

Adding to 21323455 its reverse (55432312), we get a palindrome (76755767).

The spelling of 21323455 in words is "twenty-one million, three hundred twenty-three thousand, four hundred fifty-five".