21170075 has 12 divisors (see below), whose sum is σ = 26319000. Its totient is φ = 16892160.

The previous prime is 21170053. The next prime is 21170077. The reversal of 21170075 is 57007112.

It is a happy number.

It is a de Polignac number, because none of the positive numbers 2^k-21170075 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21170075.

It is not an unprimeable number, because it can be changed into a prime (21170077) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 11627 + ... + 13323.

It is an arithmetic number, because the mean of its divisors is an integer number (2193250).

Almost surely, 2^21170075 is an apocalyptic number.

21170075 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21170075 is a deficient number, since it is larger than the sum of its proper divisors (5148925).

21170075 is a wasteful number, since it uses less digits than its factorization.

21170075 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2206 (or 2201 counting only the distinct ones).

The product of its (nonzero) digits is 490, while the sum is 23.

The square root of 21170075 is about 4601.0949783720. The cubic root of 21170075 is about 276.6352160182.

Adding to 21170075 its reverse (57007112), we get a palindrome (78177187).

The spelling of 21170075 in words is "twenty-one million, one hundred seventy thousand, seventy-five".