20315081 has 2 divisors, whose sum is σ = 20315082. Its totient is φ = 20315080.

The previous prime is 20315069. The next prime is 20315083. The reversal of 20315081 is 18051302.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14478025 + 5837056 = 3805^2 + 2416^2 .

It is a cyclic number.

It is not a de Polignac number, because 20315081 - 2¹⁸ = 20052937 is a prime.

It is a super-2 number, since 2×20315081² = 825405032073122, which contains 22 as substring.

Together with 20315083, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (20315083) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10157540 + 10157541.

It is an arithmetic number, because the mean of its divisors is an integer number (10157541).

Almost surely, 2^20315081 is an apocalyptic number.

It is an amenable number.

20315081 is a deficient number, since it is larger than the sum of its proper divisors (1).

20315081 is an equidigital number, since it uses as much as digits as its factorization.

20315081 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 240, while the sum is 20.

The square root of 20315081 is about 4507.2254214761. The cubic root of 20315081 is about 272.8597767272.

Adding to 20315081 its reverse (18051302), we get a palindrome (38366383).

The spelling of 20315081 in words is "twenty million, three hundred fifteen thousand, eighty-one".