21106375 has 8 divisors (see below), whose sum is σ = 26340912. Its totient is φ = 16885000.

The previous prime is 21106373. The next prime is 21106399. The reversal of 21106375 is 57360112.

It is not a de Polignac number, because 21106375 - 2¹ = 21106373 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (25).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21106373) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 84301 + ... + 84550.

It is an arithmetic number, because the mean of its divisors is an integer number (3292614).

Almost surely, 2^21106375 is an apocalyptic number.

21106375 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21106375 is a deficient number, since it is larger than the sum of its proper divisors (5234537).

21106375 is an equidigital number, since it uses as much as digits as its factorization.

21106375 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 168866 (or 168856 counting only the distinct ones).

The product of its (nonzero) digits is 1260, while the sum is 25.

The square root of 21106375 is about 4594.1674980349. The cubic root of 21106375 is about 276.3574754310.

Adding to 21106375 its reverse (57360112), we get a palindrome (78466487).

The spelling of 21106375 in words is "twenty-one million, one hundred six thousand, three hundred seventy-five".