21051675 has 18 divisors (see below), whose sum is σ = 37706292. Its totient is φ = 11227440.

The previous prime is 21051673. The next prime is 21051691. The reversal of 21051675 is 57615012.

It is not a de Polignac number, because 21051675 - 2¹ = 21051673 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21051673) 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 17 ways as a sum of consecutive naturals, for example, 46557 + ... + 47006.

It is an arithmetic number, because the mean of its divisors is an integer number (2094794).

Almost surely, 2^21051675 is an apocalyptic number.

21051675 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21051675 is a deficient number, since it is larger than the sum of its proper divisors (16654617).

21051675 is a wasteful number, since it uses less digits than its factorization.

21051675 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 93579 (or 93571 counting only the distinct ones).

The product of its (nonzero) digits is 2100, while the sum is 27.

The square root of 21051675 is about 4588.2104354530. The cubic root of 21051675 is about 276.1185297448.

Adding to 21051675 its reverse (57615012), we get a palindrome (78666687).

The spelling of 21051675 in words is "twenty-one million, fifty-one thousand, six hundred seventy-five".