21744649 has 12 divisors (see below), whose sum is σ = 23464624. Its totient is φ = 20142144.

The previous prime is 21744631. The next prime is 21744727. The reversal of 21744649 is 94644712.

It is a happy number.

It is not a de Polignac number, because 21744649 - 2⁵ = 21744617 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21744629) 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 11 ways as a sum of consecutive naturals, for example, 18802 + ... + 19924.

Almost surely, 2^21744649 is an apocalyptic number.

It is an amenable number.

21744649 is a deficient number, since it is larger than the sum of its proper divisors (1719975).

21744649 is a wasteful number, since it uses less digits than its factorization.

21744649 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1224 (or 1207 counting only the distinct ones).

The product of its digits is 48384, while the sum is 37.

The square root of 21744649 is about 4663.1158038376. The cubic root of 21744649 is about 279.1156152087.

The spelling of 21744649 in words is "twenty-one million, seven hundred forty-four thousand, six hundred forty-nine".