20310391 has 2 divisors, whose sum is σ = 20310392. Its totient is φ = 20310390.

The previous prime is 20310383. The next prime is 20310397. The reversal of 20310391 is 19301302.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20310391 - 2³ = 20310383 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20310397) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10155195 + 10155196.

It is an arithmetic number, because the mean of its divisors is an integer number (10155196).

Almost surely, 2^20310391 is an apocalyptic number.

20310391 is a deficient number, since it is larger than the sum of its proper divisors (1).

20310391 is an equidigital number, since it uses as much as digits as its factorization.

20310391 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 162, while the sum is 19.

The square root of 20310391 is about 4506.7051157137. The cubic root of 20310391 is about 272.8387773714.

Adding to 20310391 its reverse (19301302), we get a palindrome (39611693).

The spelling of 20310391 in words is "twenty million, three hundred ten thousand, three hundred ninety-one".