20917471 has 4 divisors (see below), whose sum is σ = 20941344. Its totient is φ = 20893600.

The previous prime is 20917459. The next prime is 20917483. The reversal of 20917471 is 17471902.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (20917459) and next prime (20917483).

It is a cyclic number.

It is not a de Polignac number, because 20917471 - 2²³ = 12528863 is a prime.

It is a super-3 number, since 3×20917471³ (a number of 23 digits) contains 333 as substring.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20917441) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10570 + ... + 12391.

It is an arithmetic number, because the mean of its divisors is an integer number (5235336).

Almost surely, 2^20917471 is an apocalyptic number.

20917471 is a deficient number, since it is larger than the sum of its proper divisors (23873).

20917471 is an equidigital number, since it uses as much as digits as its factorization.

20917471 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23872.

The product of its (nonzero) digits is 3528, while the sum is 31.

The square root of 20917471 is about 4573.5621784338. The cubic root of 20917471 is about 275.5305284663.

The spelling of 20917471 in words is "twenty million, nine hundred seventeen thousand, four hundred seventy-one".