20916649 has 8 divisors (see below), whose sum is σ = 22666112. Its totient is φ = 19187280.

The previous prime is 20916589. The next prime is 20916673. The reversal of 20916649 is 94661902.

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

It is a cyclic number.

It is not a de Polignac number, because 20916649 - 2⁷ = 20916521 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20916689) 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, 2817 + ... + 7054.

It is an arithmetic number, because the mean of its divisors is an integer number (2833264).

Almost surely, 2^20916649 is an apocalyptic number.

It is an amenable number.

20916649 is a deficient number, since it is larger than the sum of its proper divisors (1749463).

20916649 is a wasteful number, since it uses less digits than its factorization.

20916649 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10047.

The product of its (nonzero) digits is 23328, while the sum is 37.

The square root of 20916649 is about 4573.4723132430. The cubic root of 20916649 is about 275.5269192177.

The spelling of 20916649 in words is "twenty million, nine hundred sixteen thousand, six hundred forty-nine".