20315017381 has 2 divisors, whose sum is σ = 20315017382. Its totient is φ = 20315017380.

The previous prime is 20315017367. The next prime is 20315017399. The reversal of 20315017381 is 18371051302.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11525954881 + 8789062500 = 107359^2 + 93750^2 .

It is a cyclic number.

It is not a de Polignac number, because 20315017381 - 2²³ = 20306628773 is a prime.

It is a super-2 number, since 2×20315017381² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20315017081) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10157508690 + 10157508691.

It is an arithmetic number, because the mean of its divisors is an integer number (10157508691).

Almost surely, 2^20315017381 is an apocalyptic number.

It is an amenable number.

20315017381 is a deficient number, since it is larger than the sum of its proper divisors (1).

20315017381 is an equidigital number, since it uses as much as digits as its factorization.

20315017381 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5040, while the sum is 31.

Adding to 20315017381 its reverse (18371051302), we get a palindrome (38686068683).

The spelling of 20315017381 in words is "twenty billion, three hundred fifteen million, seventeen thousand, three hundred eighty-one".