21245055 has 16 divisors (see below), whose sum is σ = 36607200. Its totient is φ = 10459008.

The previous prime is 21245051. The next prime is 21245057. The reversal of 21245055 is 55054212.

It is a happy number.

It is not a de Polignac number, because 21245055 - 2² = 21245051 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21245051) 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 15 ways as a sum of consecutive naturals, for example, 54280 + ... + 54669.

It is an arithmetic number, because the mean of its divisors is an integer number (2287950).

Almost surely, 2^21245055 is an apocalyptic number.

21245055 is a deficient number, since it is larger than the sum of its proper divisors (15362145).

21245055 is a wasteful number, since it uses less digits than its factorization.

21245055 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 108970.

The product of its (nonzero) digits is 2000, while the sum is 24.

The square root of 21245055 is about 4609.2358368823. The cubic root of 21245055 is about 276.9614259866.

Adding to 21245055 its reverse (55054212), we get a palindrome (76299267).

The spelling of 21245055 in words is "twenty-one million, two hundred forty-five thousand, fifty-five".