21409875 has 24 divisors (see below), whose sum is σ = 38596896. Its totient is φ = 11418000.

The previous prime is 21409867. The next prime is 21409907. The reversal of 21409875 is 57890412.

It is not a de Polignac number, because 21409875 - 2³ = 21409867 is a prime.

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 23 ways as a sum of consecutive naturals, for example, 8391 + ... + 10640.

It is an arithmetic number, because the mean of its divisors is an integer number (1608204).

Almost surely, 2^21409875 is an apocalyptic number.

21409875 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21409875 is a deficient number, since it is larger than the sum of its proper divisors (17187021).

21409875 is a wasteful number, since it uses less digits than its factorization.

21409875 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19052 (or 19039 counting only the distinct ones).

The product of its (nonzero) digits is 20160, while the sum is 36.

The square root of 21409875 is about 4627.0806130864. The cubic root of 21409875 is about 277.6758077574.

The spelling of 21409875 in words is "twenty-one million, four hundred nine thousand, eight hundred seventy-five".