21258895 has 12 divisors (see below), whose sum is σ = 29676024. Its totient is φ = 14577360.

The previous prime is 21258871. The next prime is 21258907. The reversal of 21258895 is 59885212.

It is not a de Polignac number, because 21258895 - 2⁵ = 21258863 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 (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 43141 + ... + 43630.

It is an arithmetic number, because the mean of its divisors is an integer number (2473002).

Almost surely, 2^21258895 is an apocalyptic number.

21258895 is a deficient number, since it is larger than the sum of its proper divisors (8417129).

21258895 is an equidigital number, since it uses as much as digits as its factorization.

21258895 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 86790 (or 86783 counting only the distinct ones).

The product of its digits is 57600, while the sum is 40.

The square root of 21258895 is about 4610.7369259154. The cubic root of 21258895 is about 277.0215547094.

The spelling of 21258895 in words is "twenty-one million, two hundred fifty-eight thousand, eight hundred ninety-five".