21744861 has 8 divisors (see below), whose sum is σ = 29264544. Its totient is φ = 14360880.

The previous prime is 21744859. The next prime is 21744907. The reversal of 21744861 is 16844712.

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

It is not a de Polignac number, because 21744861 - 2¹ = 21744859 is a prime.

It is a plaindrome in base 16.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21744841) 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, 33550 + ... + 34191.

It is an arithmetic number, because the mean of its divisors is an integer number (3658068).

Almost surely, 2^21744861 is an apocalyptic number.

It is an amenable number.

21744861 is a deficient number, since it is larger than the sum of its proper divisors (7519683).

21744861 is a wasteful number, since it uses less digits than its factorization.

21744861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 67851.

The product of its digits is 10752, while the sum is 33.

The square root of 21744861 is about 4663.1385353644. The cubic root of 21744861 is about 279.1165222873.

The spelling of 21744861 in words is "twenty-one million, seven hundred forty-four thousand, eight hundred sixty-one".