20911649 has 8 divisors (see below), whose sum is σ = 24154848. Its totient is φ = 17892160.

The previous prime is 20911637. The next prime is 20911651. The reversal of 20911649 is 94611902.

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

It is not a de Polignac number, because 20911649 - 2²⁰ = 19863073 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20911619) 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, 55727 + ... + 56100.

It is an arithmetic number, because the mean of its divisors is an integer number (3019356).

Almost surely, 2^20911649 is an apocalyptic number.

It is an amenable number.

20911649 is a deficient number, since it is larger than the sum of its proper divisors (3243199).

20911649 is a wasteful number, since it uses less digits than its factorization.

20911649 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 111855.

The product of its (nonzero) digits is 3888, while the sum is 32.

The square root of 20911649 is about 4572.9256499532. The cubic root of 20911649 is about 275.5049631134.

The spelling of 20911649 in words is "twenty million, nine hundred eleven thousand, six hundred forty-nine".