20491371 has 12 divisors (see below), whose sum is σ = 30619680. Its totient is φ = 13189680.

The previous prime is 20491369. The next prime is 20491379. The reversal of 20491371 is 17319402.

20491371 is a `hidden beast` number, since 204 + 91 + 371 = 666.

It is not a de Polignac number, because 20491371 - 2¹ = 20491369 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20491379) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 38995 + ... + 39516.

It is an arithmetic number, because the mean of its divisors is an integer number (2551640).

Almost surely, 2^20491371 is an apocalyptic number.

20491371 is a deficient number, since it is larger than the sum of its proper divisors (10128309).

20491371 is a wasteful number, since it uses less digits than its factorization.

20491371 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 78546 (or 78543 counting only the distinct ones).

The product of its (nonzero) digits is 1512, while the sum is 27.

The square root of 20491371 is about 4526.7395551324. The cubic root of 20491371 is about 273.6467778719.

The spelling of 20491371 in words is "twenty million, four hundred ninety-one thousand, three hundred seventy-one".