20320242457 has 2 divisors, whose sum is σ = 20320242458. Its totient is φ = 20320242456.

The previous prime is 20320242433. The next prime is 20320242479. The reversal of 20320242457 is 75424202302.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16693673616 + 3626568841 = 129204^2 + 60221^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20320242457 is a prime.

It is a super-2 number, since 2×20320242457² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (20320242427) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10160121228 + 10160121229.

It is an arithmetic number, because the mean of its divisors is an integer number (10160121229).

Almost surely, 2^20320242457 is an apocalyptic number.

It is an amenable number.

20320242457 is a deficient number, since it is larger than the sum of its proper divisors (1).

20320242457 is an equidigital number, since it uses as much as digits as its factorization.

20320242457 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 26880, while the sum is 31.

Adding to 20320242457 its reverse (75424202302), we get a palindrome (95744444759).

The spelling of 20320242457 in words is "twenty billion, three hundred twenty million, two hundred forty-two thousand, four hundred fifty-seven".