21891241 has 8 divisors (see below), whose sum is σ = 22256640. Its totient is φ = 21528672.

The previous prime is 21891227. The next prime is 21891269. The reversal of 21891241 is 14219812.

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 21891241 - 2⁵ = 21891209 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21891281) 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, 19296 + ... + 20398.

It is an arithmetic number, because the mean of its divisors is an integer number (2782080).

Almost surely, 2^21891241 is an apocalyptic number.

It is an amenable number.

21891241 is a deficient number, since it is larger than the sum of its proper divisors (365399).

21891241 is a wasteful number, since it uses less digits than its factorization.

21891241 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1415.

The product of its digits is 1152, while the sum is 28.

The square root of 21891241 is about 4678.8076472537. The cubic root of 21891241 is about 279.7414322158.

The spelling of 21891241 in words is "twenty-one million, eight hundred ninety-one thousand, two hundred forty-one".