21544791 has 4 divisors (see below), whose sum is σ = 28726392. Its totient is φ = 14363192.

The previous prime is 21544759. The next prime is 21544799. The reversal of 21544791 is 19744512.

It is a happy number.

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 21544791 - 2⁵ = 21544759 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21544799) 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, 3590796 + ... + 3590801.

It is an arithmetic number, because the mean of its divisors is an integer number (7181598).

Almost surely, 2^21544791 is an apocalyptic number.

21544791 is a deficient number, since it is larger than the sum of its proper divisors (7181601).

21544791 is an equidigital number, since it uses as much as digits as its factorization.

21544791 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7181600.

The product of its digits is 10080, while the sum is 33.

The square root of 21544791 is about 4641.6366725542. The cubic root of 21544791 is about 278.2578521302.

The spelling of 21544791 in words is "twenty-one million, five hundred forty-four thousand, seven hundred ninety-one".