21252055 has 8 divisors (see below), whose sum is σ = 27820944. Its totient is φ = 15456000.

The previous prime is 21252047. The next prime is 21252059. The reversal of 21252055 is 55025212.

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

It is not a de Polignac number, because 21252055 - 2³ = 21252047 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 (21252059) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 193146 + ... + 193255.

It is an arithmetic number, because the mean of its divisors is an integer number (3477618).

Almost surely, 2^21252055 is an apocalyptic number.

21252055 is a deficient number, since it is larger than the sum of its proper divisors (6568889).

21252055 is a wasteful number, since it uses less digits than its factorization.

21252055 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 386417.

The product of its (nonzero) digits is 1000, while the sum is 22.

The square root of 21252055 is about 4609.9951193033. The cubic root of 21252055 is about 276.9918411756.

Adding to 21252055 its reverse (55025212), we get a palindrome (76277267).

The spelling of 21252055 in words is "twenty-one million, two hundred fifty-two thousand, fifty-five".