21143875 has 8 divisors (see below), whose sum is σ = 26387712. Its totient is φ = 16915000.

The previous prime is 21143867. The next prime is 21143879. The reversal of 21143875 is 57834112.

It is not a de Polignac number, because 21143875 - 2³ = 21143867 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21143879) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 84451 + ... + 84700.

It is an arithmetic number, because the mean of its divisors is an integer number (3298464).

Almost surely, 2^21143875 is an apocalyptic number.

21143875 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21143875 is a deficient number, since it is larger than the sum of its proper divisors (5243837).

21143875 is an equidigital number, since it uses as much as digits as its factorization.

21143875 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 169166 (or 169156 counting only the distinct ones).

The product of its digits is 6720, while the sum is 31.

The square root of 21143875 is about 4598.2469485664. The cubic root of 21143875 is about 276.5210480289.

Adding to 21143875 its reverse (57834112), we get a palindrome (78977987).

The spelling of 21143875 in words is "twenty-one million, one hundred forty-three thousand, eight hundred seventy-five".