20315307421 has 2 divisors, whose sum is σ = 20315307422. Its totient is φ = 20315307420.

The previous prime is 20315307413. The next prime is 20315307499. The reversal of 20315307421 is 12470351302.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20269216900 + 46090521 = 142370^2 + 6789^2 .

It is a cyclic number.

It is not a de Polignac number, because 20315307421 - 2³ = 20315307413 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20315307421.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20315307821) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10157653710 + 10157653711.

It is an arithmetic number, because the mean of its divisors is an integer number (10157653711).

Almost surely, 2^20315307421 is an apocalyptic number.

It is an amenable number.

20315307421 is a deficient number, since it is larger than the sum of its proper divisors (1).

20315307421 is an equidigital number, since it uses as much as digits as its factorization.

20315307421 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 28.

Adding to 20315307421 its reverse (12470351302), we get a palindrome (32785658723).

The spelling of 20315307421 in words is "twenty billion, three hundred fifteen million, three hundred seven thousand, four hundred twenty-one".