21252455 has 8 divisors (see below), whose sum is σ = 29146272. Its totient is φ = 14573088.

The previous prime is 21252443. The next prime is 21252457. The reversal of 21252455 is 55425212.

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 21252455 - 2¹⁸ = 20990311 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21252457) 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, 303572 + ... + 303641.

It is an arithmetic number, because the mean of its divisors is an integer number (3643284).

Almost surely, 2^21252455 is an apocalyptic number.

21252455 is a deficient number, since it is larger than the sum of its proper divisors (7893817).

21252455 is an equidigital number, since it uses as much as digits as its factorization.

21252455 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 607225.

The product of its digits is 4000, while the sum is 26.

The square root of 21252455 is about 4610.0385030930. The cubic root of 21252455 is about 276.9935789846.

Adding to 21252455 its reverse (55425212), we get a palindrome (76677667).

The spelling of 21252455 in words is "twenty-one million, two hundred fifty-two thousand, four hundred fifty-five".