21168291 has 8 divisors (see below), whose sum is σ = 28257984. Its totient is φ = 14095400.

The previous prime is 21168271. The next prime is 21168293. The reversal of 21168291 is 19286112.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21168291 - 2¹⁹ = 20644003 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21168293) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 885 + ... + 6566.

It is an arithmetic number, because the mean of its divisors is an integer number (3532248).

Almost surely, 2^21168291 is an apocalyptic number.

21168291 is a deficient number, since it is larger than the sum of its proper divisors (7089693).

21168291 is an equidigital number, since it uses as much as digits as its factorization.

21168291 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8401.

The product of its digits is 1728, while the sum is 30.

The square root of 21168291 is about 4600.9011073919. The cubic root of 21168291 is about 276.6274451263.

The spelling of 21168291 in words is "twenty-one million, one hundred sixty-eight thousand, two hundred ninety-one".