20191971 has 8 divisors (see below), whose sum is σ = 28506384. Its totient is φ = 12669440.

The previous prime is 20191931. The next prime is 20191987. The reversal of 20191971 is 17919102.

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 20191971 - 2⁹ = 20191459 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20191931) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 197910 + ... + 198011.

It is an arithmetic number, because the mean of its divisors is an integer number (3563298).

Almost surely, 2^20191971 is an apocalyptic number.

20191971 is a deficient number, since it is larger than the sum of its proper divisors (8314413).

20191971 is a wasteful number, since it uses less digits than its factorization.

20191971 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 395941.

The product of its (nonzero) digits is 1134, while the sum is 30.

The square root of 20191971 is about 4493.5477075469. The cubic root of 20191971 is about 272.3074800994.

The spelling of 20191971 in words is "twenty million, one hundred ninety-one thousand, nine hundred seventy-one".