20181071 has 4 divisors (see below), whose sum is σ = 20877000. Its totient is φ = 19485144.

The previous prime is 20181053. The next prime is 20181079. The reversal of 20181071 is 17018102.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20181071 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 (20181079) 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, 347921 + ... + 347978.

It is an arithmetic number, because the mean of its divisors is an integer number (5219250).

Almost surely, 2^20181071 is an apocalyptic number.

20181071 is a deficient number, since it is larger than the sum of its proper divisors (695929).

20181071 is an equidigital number, since it uses as much as digits as its factorization.

20181071 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 695928.

The product of its (nonzero) digits is 112, while the sum is 20.

The square root of 20181071 is about 4492.3346936754. The cubic root of 20181071 is about 272.2584724058.

Adding to 20181071 its reverse (17018102), we get a palindrome (37199173).

The spelling of 20181071 in words is "twenty million, one hundred eighty-one thousand, seventy-one".