20199971 has 8 divisors (see below), whose sum is σ = 22161600. Its totient is φ = 18259240.

The previous prime is 20199953. The next prime is 20199973. The reversal of 20199971 is 17999102.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 20199971 - 2¹⁰ = 20198947 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20199973) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3161 + ... + 7098.

It is an arithmetic number, because the mean of its divisors is an integer number (2770200).

Almost surely, 2^20199971 is an apocalyptic number.

20199971 is a deficient number, since it is larger than the sum of its proper divisors (1961629).

20199971 is a wasteful number, since it uses less digits than its factorization.

20199971 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10449.

The product of its (nonzero) digits is 10206, while the sum is 38.

The square root of 20199971 is about 4494.4377846400. The cubic root of 20199971 is about 272.3434378274.

It can be divided in two parts, 20 and 199971, that added together give a palindrome (199991).

The spelling of 20199971 in words is "twenty million, one hundred ninety-nine thousand, nine hundred seventy-one".