21736649 has 8 divisors (see below), whose sum is σ = 24354048. Its totient is φ = 19226160.

The previous prime is 21736619. The next prime is 21736657. The reversal of 21736649 is 94663712.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21736649 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21736619) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 26297 + ... + 27110.

It is an arithmetic number, because the mean of its divisors is an integer number (3044256).

Almost surely, 2^21736649 is an apocalyptic number.

It is an amenable number.

21736649 is a deficient number, since it is larger than the sum of its proper divisors (2617399).

21736649 is a wasteful number, since it uses less digits than its factorization.

21736649 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 53455.

The product of its digits is 54432, while the sum is 38.

The square root of 21736649 is about 4662.2579293728. The cubic root of 21736649 is about 279.0813815172.

The spelling of 21736649 in words is "twenty-one million, seven hundred thirty-six thousand, six hundred forty-nine".