20971191 has 8 divisors (see below), whose sum is σ = 27984880. Its totient is φ = 13969152.

The previous prime is 20971157. The next prime is 20971219. The reversal of 20971191 is 19117902.

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

It is not a de Polignac number, because 20971191 - 2⁶ = 20971127 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 (20971121) 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, 3015 + ... + 7143.

It is an arithmetic number, because the mean of its divisors is an integer number (3498110).

Almost surely, 2^20971191 is an apocalyptic number.

20971191 is a deficient number, since it is larger than the sum of its proper divisors (7013689).

20971191 is a wasteful number, since it uses less digits than its factorization.

20971191 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5825.

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

The square root of 20971191 is about 4579.4312965695. The cubic root of 20971191 is about 275.7661982409.

The spelling of 20971191 in words is "twenty million, nine hundred seventy-one thousand, one hundred ninety-one".