21112775 has 6 divisors (see below), whose sum is σ = 26179872. Its totient is φ = 16890200.

The previous prime is 21112769. The next prime is 21112787. The reversal of 21112775 is 57721112.

It is not a de Polignac number, because 21112775 - 2⁶ = 21112711 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 422231 + ... + 422280.

It is an arithmetic number, because the mean of its divisors is an integer number (4363312).

Almost surely, 2^21112775 is an apocalyptic number.

21112775 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21112775 is a deficient number, since it is larger than the sum of its proper divisors (5067097).

21112775 is an equidigital number, since it uses as much as digits as its factorization.

21112775 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 844521 (or 844516 counting only the distinct ones).

The product of its digits is 980, while the sum is 26.

The square root of 21112775 is about 4594.8639805766. The cubic root of 21112775 is about 276.3854055248.

Adding to 21112775 its reverse (57721112), we get a palindrome (78833887).

The spelling of 21112775 in words is "twenty-one million, one hundred twelve thousand, seven hundred seventy-five".