20865394171 has 4 divisors (see below), whose sum is σ = 20871944392. Its totient is φ = 20858843952.

The previous prime is 20865394169. The next prime is 20865394181. The reversal of 20865394171 is 17149356802.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 17149356802 = 2 ⋅8574678401.

It is a cyclic number.

It is not a de Polignac number, because 20865394171 - 2¹ = 20865394169 is a prime.

It is a super-2 number, since 2×20865394171² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20865394181) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3270330 + ... + 3276703.

It is an arithmetic number, because the mean of its divisors is an integer number (5217986098).

It is a 1-persistent number, because it is pandigital, but 2⋅20865394171 = 41730788342 is not.

Almost surely, 2^20865394171 is an apocalyptic number.

20865394171 is a deficient number, since it is larger than the sum of its proper divisors (6550221).

20865394171 is an equidigital number, since it uses as much as digits as its factorization.

20865394171 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6550220.

The product of its (nonzero) digits is 362880, while the sum is 46.

The spelling of 20865394171 in words is "twenty billion, eight hundred sixty-five million, three hundred ninety-four thousand, one hundred seventy-one".