21068649 has 12 divisors (see below), whose sum is σ = 34780096. Its totient is φ = 12039192.

The previous prime is 21068617. The next prime is 21068653. The reversal of 21068649 is 94686012.

21068649 is a `hidden beast` number, since 2 + 1 + 0 + 6 + 8 + 649 = 666.

It is not a de Polignac number, because 21068649 - 2⁵ = 21068617 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21068609) 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 11 ways as a sum of consecutive naturals, for example, 167149 + ... + 167274.

Almost surely, 2^21068649 is an apocalyptic number.

It is an amenable number.

21068649 is a deficient number, since it is larger than the sum of its proper divisors (13711447).

21068649 is a wasteful number, since it uses less digits than its factorization.

21068649 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 334436 (or 334433 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 36.

The square root of 21068649 is about 4590.0598035320. The cubic root of 21068649 is about 276.1927214155.

The spelling of 21068649 in words is "twenty-one million, sixty-eight thousand, six hundred forty-nine".