21676649 has 8 divisors (see below), whose sum is σ = 23950080. Its totient is φ = 19514176.

The previous prime is 21676643. The next prime is 21676661. The reversal of 21676649 is 94667612.

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-21676649 is a prime.

It is a super-2 number, since 2×21676649² = 939754223738402, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21676643) 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 7 ways as a sum of consecutive naturals, for example, 27329 + ... + 28110.

It is an arithmetic number, because the mean of its divisors is an integer number (2993760).

Almost surely, 2^21676649 is an apocalyptic number.

It is an amenable number.

21676649 is a deficient number, since it is larger than the sum of its proper divisors (2273431).

21676649 is a wasteful number, since it uses less digits than its factorization.

21676649 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55479.

The product of its digits is 108864, while the sum is 41.

The square root of 21676649 is about 4655.8188323860. The cubic root of 21676649 is about 278.8243607040.

The spelling of 21676649 in words is "twenty-one million, six hundred seventy-six thousand, six hundred forty-nine".