21753873 has 16 divisors (see below), whose sum is σ = 32381440. Its totient is φ = 14433552.

The previous prime is 21753871. The next prime is 21753877. The reversal of 21753873 is 37835712.

It is not a de Polignac number, because 21753873 - 2¹ = 21753871 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21753871) 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 15 ways as a sum of consecutive naturals, for example, 4215 + ... + 7827.

It is an arithmetic number, because the mean of its divisors is an integer number (2023840).

Almost surely, 2^21753873 is an apocalyptic number.

It is an amenable number.

21753873 is a deficient number, since it is larger than the sum of its proper divisors (10627567).

21753873 is a wasteful number, since it uses less digits than its factorization.

21753873 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3845 (or 3839 counting only the distinct ones).

The product of its digits is 35280, while the sum is 36.

The square root of 21753873 is about 4664.1047372459. The cubic root of 21753873 is about 279.1550762347.

The spelling of 21753873 in words is "twenty-one million, seven hundred fifty-three thousand, eight hundred seventy-three".