21182851 has 4 divisors (see below), whose sum is σ = 21206304. Its totient is φ = 21159400.

The previous prime is 21182849. The next prime is 21182857. The reversal of 21182851 is 15828112.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21182851 - 2¹ = 21182849 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21182857) 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 3 ways as a sum of consecutive naturals, for example, 10315 + ... + 12196.

It is an arithmetic number, because the mean of its divisors is an integer number (5301576).

Almost surely, 2^21182851 is an apocalyptic number.

21182851 is a deficient number, since it is larger than the sum of its proper divisors (23453).

21182851 is an equidigital number, since it uses as much as digits as its factorization.

21182851 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23452.

The product of its digits is 1280, while the sum is 28.

The square root of 21182851 is about 4602.4831341353. The cubic root of 21182851 is about 276.6908540006.

The spelling of 21182851 in words is "twenty-one million, one hundred eighty-two thousand, eight hundred fifty-one".