20809271 has 6 divisors (see below), whose sum is σ = 24206760. Its totient is φ = 17836476.

The previous prime is 20809249. The next prime is 20809279. The reversal of 20809271 is 17290802.

It is a happy number.

It is not a de Polignac number, because 20809271 - 2¹⁰ = 20808247 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 (20809279) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 212291 + ... + 212388.

It is an arithmetic number, because the mean of its divisors is an integer number (4034460).

Almost surely, 2^20809271 is an apocalyptic number.

20809271 is a deficient number, since it is larger than the sum of its proper divisors (3397489).

20809271 is an equidigital number, since it uses as much as digits as its factorization.

20809271 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 424693 (or 424686 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 29.

The square root of 20809271 is about 4561.7179877761. The cubic root of 20809271 is about 275.0546271644.

The spelling of 20809271 in words is "twenty million, eight hundred nine thousand, two hundred seventy-one".