21789573 has 16 divisors (see below), whose sum is σ = 32053056. Its totient is φ = 13080960.

The previous prime is 21789571. The next prime is 21789577. The reversal of 21789573 is 37598712.

It is not a de Polignac number, because 21789573 - 2¹ = 21789571 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21789571) 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, 5215 + ... + 8412.

It is an arithmetic number, because the mean of its divisors is an integer number (2003316).

Almost surely, 2^21789573 is an apocalyptic number.

It is an amenable number.

21789573 is a deficient number, since it is larger than the sum of its proper divisors (10263483).

21789573 is a wasteful number, since it uses less digits than its factorization.

21789573 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13684.

The product of its digits is 105840, while the sum is 42.

The square root of 21789573 is about 4667.9302694021. The cubic root of 21789573 is about 279.3076987062.

The spelling of 21789573 in words is "twenty-one million, seven hundred eighty-nine thousand, five hundred seventy-three".