21041775 has 30 divisors (see below), whose sum is σ = 38980392. Its totient is φ = 11221200.

The previous prime is 21041771. The next prime is 21041807. The reversal of 21041775 is 57714012.

It is not a de Polignac number, because 21041775 - 2² = 21041771 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21041771) 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 29 ways as a sum of consecutive naturals, for example, 3171 + ... + 7220.

Almost surely, 2^21041775 is an apocalyptic number.

21041775 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21041775 is a deficient number, since it is larger than the sum of its proper divisors (17938617).

21041775 is a wasteful number, since it uses less digits than its factorization.

21041775 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10413 (or 10399 counting only the distinct ones).

The product of its (nonzero) digits is 1960, while the sum is 27.

The square root of 21041775 is about 4587.1314565859. The cubic root of 21041775 is about 276.0752394118.

Adding to 21041775 its reverse (57714012), we get a palindrome (78755787).

The spelling of 21041775 in words is "twenty-one million, forty-one thousand, seven hundred seventy-five".