20311381 has 2 divisors, whose sum is σ = 20311382. Its totient is φ = 20311380.

The previous prime is 20311363. The next prime is 20311433. The reversal of 20311381 is 18311302.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13727025 + 6584356 = 3705^2 + 2566^2 .

It is a cyclic number.

It is not a de Polignac number, because 20311381 - 2¹⁵ = 20278613 is a prime.

It is a super-2 number, since 2×20311381² = 825104396254322, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20311321) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10155690 + 10155691.

It is an arithmetic number, because the mean of its divisors is an integer number (10155691).

Almost surely, 2^20311381 is an apocalyptic number.

It is an amenable number.

20311381 is a deficient number, since it is larger than the sum of its proper divisors (1).

20311381 is an equidigital number, since it uses as much as digits as its factorization.

20311381 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 144, while the sum is 19.

The square root of 20311381 is about 4506.8149507163. The cubic root of 20311381 is about 272.8432103404.

Adding to 20311381 its reverse (18311302), we get a palindrome (38622683).

The spelling of 20311381 in words is "twenty million, three hundred eleven thousand, three hundred eighty-one".