21825855 has 20 divisors (see below), whose sum is σ = 39125592. Its totient is φ = 11640240.

The previous prime is 21825757. The next prime is 21825887. The reversal of 21825855 is 55852812.

It is not a de Polignac number, because 21825855 - 2⁸ = 21825599 is a prime.

It is a congruent number.

It is an unprimeable number.

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 19 ways as a sum of consecutive naturals, for example, 26541 + ... + 27350.

Almost surely, 2^21825855 is an apocalyptic number.

21825855 is a deficient number, since it is larger than the sum of its proper divisors (17299737).

21825855 is an equidigital number, since it uses as much as digits as its factorization.

21825855 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 53908 (or 53899 counting only the distinct ones).

The product of its digits is 32000, while the sum is 36.

The square root of 21825855 is about 4671.8149578082. The cubic root of 21825855 is about 279.4626386014.

The spelling of 21825855 in words is "twenty-one million, eight hundred twenty-five thousand, eight hundred fifty-five".