20271491 has 2 divisors, whose sum is σ = 20271492. Its totient is φ = 20271490.

The previous prime is 20271481. The next prime is 20271521. The reversal of 20271491 is 19417202.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20271491 - 2¹⁸ = 20009347 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20271491.

It is not a weakly prime, because it can be changed into another prime (20271401) 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 as a sum of consecutive naturals, namely, 10135745 + 10135746.

It is an arithmetic number, because the mean of its divisors is an integer number (10135746).

Almost surely, 2^20271491 is an apocalyptic number.

20271491 is a deficient number, since it is larger than the sum of its proper divisors (1).

20271491 is an equidigital number, since it uses as much as digits as its factorization.

20271491 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1008, while the sum is 26.

The square root of 20271491 is about 4502.3872556678. The cubic root of 20271491 is about 272.6644788799.

Adding to 20271491 its reverse (19417202), we get a palindrome (39688693).

The spelling of 20271491 in words is "twenty million, two hundred seventy-one thousand, four hundred ninety-one".