21775245 has 16 divisors (see below), whose sum is σ = 34904832. Its totient is φ = 11592000.

The previous prime is 21775219. The next prime is 21775261. The reversal of 21775245 is 54257712.

It is not a de Polignac number, because 21775245 - 2⁹ = 21774733 is a prime.

It is a super-2 number, since 2×21775245² = 948322589620050, which contains 22 as substring.

It is a congruent number.

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 15 ways as a sum of consecutive naturals, for example, 10299 + ... + 12231.

It is an arithmetic number, because the mean of its divisors is an integer number (2181552).

Almost surely, 2^21775245 is an apocalyptic number.

It is an amenable number.

21775245 is a deficient number, since it is larger than the sum of its proper divisors (13129587).

21775245 is a wasteful number, since it uses less digits than its factorization.

21775245 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2692.

The product of its digits is 19600, while the sum is 33.

The square root of 21775245 is about 4666.3952897285. The cubic root of 21775245 is about 279.2464645523.

The spelling of 21775245 in words is "twenty-one million, seven hundred seventy-five thousand, two hundred forty-five".