21170523 has 12 divisors (see below), whose sum is σ = 31027304. Its totient is φ = 12830400.

The previous prime is 21170521. The next prime is 21170533. The reversal of 21170523 is 32507112.

It is not a de Polignac number, because 21170523 - 2¹ = 21170521 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21170523.

It is not an unprimeable number, because it can be changed into a prime (21170521) 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 11 ways as a sum of consecutive naturals, for example, 28798 + ... + 29523.

Almost surely, 2^21170523 is an apocalyptic number.

21170523 is a deficient number, since it is larger than the sum of its proper divisors (9856781).

21170523 is a wasteful number, since it uses less digits than its factorization.

21170523 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 58346 (or 58335 counting only the distinct ones).

The product of its (nonzero) digits is 420, while the sum is 21.

The square root of 21170523 is about 4601.1436621779. The cubic root of 21170523 is about 276.6371673843.

Adding to 21170523 its reverse (32507112), we get a palindrome (53677635).

The spelling of 21170523 in words is "twenty-one million, one hundred seventy thousand, five hundred twenty-three".