20271391 has 4 divisors (see below), whose sum is σ = 23167312. Its totient is φ = 17375472.

The previous prime is 20271373. The next prime is 20271401. The reversal of 20271391 is 19317202.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 20271391 - 2⁹ = 20270879 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20271331) 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 3 ways as a sum of consecutive naturals, for example, 1447950 + ... + 1447963.

It is an arithmetic number, because the mean of its divisors is an integer number (5791828).

Almost surely, 2^20271391 is an apocalyptic number.

20271391 is a deficient number, since it is larger than the sum of its proper divisors (2895921).

20271391 is an equidigital number, since it uses as much as digits as its factorization.

20271391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2895920.

The product of its (nonzero) digits is 756, while the sum is 25.

The square root of 20271391 is about 4502.3761504343. The cubic root of 20271391 is about 272.6640305246.

Adding to 20271391 its reverse (19317202), we get a palindrome (39588593).

The spelling of 20271391 in words is "twenty million, two hundred seventy-one thousand, three hundred ninety-one".