21894171 has 8 divisors (see below), whose sum is σ = 31437840. Its totient is φ = 13473312.

The previous prime is 21894167. The next prime is 21894211. The reversal of 21894171 is 17149812.

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

It is not a de Polignac number, because 21894171 - 2² = 21894167 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21894071) 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 7 ways as a sum of consecutive naturals, for example, 280656 + ... + 280733.

It is an arithmetic number, because the mean of its divisors is an integer number (3929730).

Almost surely, 2^21894171 is an apocalyptic number.

21894171 is a deficient number, since it is larger than the sum of its proper divisors (9543669).

21894171 is a wasteful number, since it uses less digits than its factorization.

21894171 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 561405.

The product of its digits is 4032, while the sum is 33.

The square root of 21894171 is about 4679.1207507394. The cubic root of 21894171 is about 279.7539121818.

It can be divided in two parts, 2189 and 4171, that multiplied together give a palindrome (9130319).

The spelling of 21894171 in words is "twenty-one million, eight hundred ninety-four thousand, one hundred seventy-one".