21051759 has 16 divisors (see below), whose sum is σ = 29528064. Its totient is φ = 13322400.

The previous prime is 21051749. The next prime is 21051761. The reversal of 21051759 is 95715012.

It is not a de Polignac number, because 21051759 - 2⁴ = 21051743 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21051749) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2794 + ... + 7064.

It is an arithmetic number, because the mean of its divisors is an integer number (1845504).

Almost surely, 2^21051759 is an apocalyptic number.

21051759 is a deficient number, since it is larger than the sum of its proper divisors (8476305).

21051759 is a wasteful number, since it uses less digits than its factorization.

21051759 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4358.

The product of its (nonzero) digits is 3150, while the sum is 30.

The square root of 21051759 is about 4588.2195893396. The cubic root of 21051759 is about 276.1188969986.

The spelling of 21051759 in words is "twenty-one million, fifty-one thousand, seven hundred fifty-nine".