20891317 has 8 divisors (see below), whose sum is σ = 23284800. Its totient is φ = 18627264.

The previous prime is 20891293. The next prime is 20891333. The reversal of 20891317 is 71319802.

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 20891317 - 2¹¹ = 20889269 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20895317) 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, 32017 + ... + 32662.

It is an arithmetic number, because the mean of its divisors is an integer number (2910600).

Almost surely, 2^20891317 is an apocalyptic number.

It is an amenable number.

20891317 is a deficient number, since it is larger than the sum of its proper divisors (2393483).

20891317 is a wasteful number, since it uses less digits than its factorization.

20891317 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 64715.

The product of its (nonzero) digits is 3024, while the sum is 31.

The square root of 20891317 is about 4570.7020248535. The cubic root of 20891317 is about 275.4156447415.

The spelling of 20891317 in words is "twenty million, eight hundred ninety-one thousand, three hundred seventeen".