21165753 has 16 divisors (see below), whose sum is σ = 33950720. Its totient is φ = 11457936.

The previous prime is 21165733. The next prime is 21165757. The reversal of 21165753 is 35756112.

It is not a de Polignac number, because 21165753 - 2⁹ = 21165241 is a prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21165753.

It is not an unprimeable number, because it can be changed into a prime (21165757) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 26125 + ... + 26922.

It is an arithmetic number, because the mean of its divisors is an integer number (2121920).

Almost surely, 2^21165753 is an apocalyptic number.

It is an amenable number.

21165753 is a deficient number, since it is larger than the sum of its proper divisors (12784967).

21165753 is a wasteful number, since it uses less digits than its factorization.

21165753 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53076.

The product of its digits is 6300, while the sum is 30.

The square root of 21165753 is about 4600.6252835892. The cubic root of 21165753 is about 276.6163891477.

The spelling of 21165753 in words is "twenty-one million, one hundred sixty-five thousand, seven hundred fifty-three".