20656271 has 4 divisors (see below), whose sum is σ = 20681232. Its totient is φ = 20631312.

The previous prime is 20656253. The next prime is 20656291. The reversal of 20656271 is 17265602.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 17265602 = 2 ⋅8632801.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20656271 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 (20656201) 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 3 ways as a sum of consecutive naturals, for example, 11195 + ... + 12908.

It is an arithmetic number, because the mean of its divisors is an integer number (5170308).

Almost surely, 2^20656271 is an apocalyptic number.

20656271 is a deficient number, since it is larger than the sum of its proper divisors (24961).

20656271 is an equidigital number, since it uses as much as digits as its factorization.

20656271 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24960.

The product of its (nonzero) digits is 5040, while the sum is 29.

The square root of 20656271 is about 4544.9170509482. The cubic root of 20656271 is about 274.3788559259.

The spelling of 20656271 in words is "twenty million, six hundred fifty-six thousand, two hundred seventy-one".