20135420257 has 2 divisors, whose sum is σ = 20135420258. Its totient is φ = 20135420256.

The previous prime is 20135420237. The next prime is 20135420363. The reversal of 20135420257 is 75202453102.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19810844001 + 324576256 = 140751^2 + 18016^2 .

It is a cyclic number.

It is not a de Polignac number, because 20135420257 - 2¹¹ = 20135418209 is a prime.

It is not a weakly prime, because it can be changed into another prime (20135420237) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10067710128 + 10067710129.

It is an arithmetic number, because the mean of its divisors is an integer number (10067710129).

Almost surely, 2^20135420257 is an apocalyptic number.

It is an amenable number.

20135420257 is a deficient number, since it is larger than the sum of its proper divisors (1).

20135420257 is an equidigital number, since it uses as much as digits as its factorization.

20135420257 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 16800, while the sum is 31.

Adding to 20135420257 its reverse (75202453102), we get a palindrome (95337873359).

The spelling of 20135420257 in words is "twenty billion, one hundred thirty-five million, four hundred twenty thousand, two hundred fifty-seven".