21994775 has 24 divisors (see below), whose sum is σ = 30044208. Its totient is φ = 15972000.

The previous prime is 21994759. The next prime is 21994781. The reversal of 21994775 is 57749912.

It is not a de Polignac number, because 21994775 - 2⁴ = 21994759 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 23 ways as a sum of consecutive naturals, for example, 32945 + ... + 33605.

It is an arithmetic number, because the mean of its divisors is an integer number (1251842).

Almost surely, 2^21994775 is an apocalyptic number.

21994775 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21994775 is a deficient number, since it is larger than the sum of its proper divisors (8049433).

21994775 is an equidigital number, since it uses as much as digits as its factorization.

21994775 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 704 (or 677 counting only the distinct ones).

The product of its digits is 158760, while the sum is 44.

The square root of 21994775 is about 4689.8587398769. The cubic root of 21994775 is about 280.1817484978.

It can be divided in two parts, 219947 and 75, that added together give a palindrome (220022).

The spelling of 21994775 in words is "twenty-one million, nine hundred ninety-four thousand, seven hundred seventy-five".