21851327 has 4 divisors (see below), whose sum is σ = 22114680. Its totient is φ = 21587976.

The previous prime is 21851293. The next prime is 21851329. The reversal of 21851327 is 72315812.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21851327 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21851327.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21851329) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 131552 + ... + 131717.

It is an arithmetic number, because the mean of its divisors is an integer number (5528670).

Almost surely, 2^21851327 is an apocalyptic number.

21851327 is a deficient number, since it is larger than the sum of its proper divisors (263353).

21851327 is an equidigital number, since it uses as much as digits as its factorization.

21851327 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 263352.

The product of its digits is 3360, while the sum is 29.

The square root of 21851327 is about 4674.5402982539. The cubic root of 21851327 is about 279.5713125404.

The spelling of 21851327 in words is "twenty-one million, eight hundred fifty-one thousand, three hundred twenty-seven".