20434020557 has 2 divisors, whose sum is σ = 20434020558. Its totient is φ = 20434020556.

The previous prime is 20434020539. The next prime is 20434020569. The reversal of 20434020557 is 75502043402.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11995944676 + 8438075881 = 109526^2 + 91859^2 .

It is a cyclic number.

It is not a de Polignac number, because 20434020557 - 2²² = 20429826253 is a prime.

It is a super-2 number, since 2×20434020557² (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 (20434020857) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10217010278 + 10217010279.

It is an arithmetic number, because the mean of its divisors is an integer number (10217010279).

Almost surely, 2^20434020557 is an apocalyptic number.

It is an amenable number.

20434020557 is a deficient number, since it is larger than the sum of its proper divisors (1).

20434020557 is an equidigital number, since it uses as much as digits as its factorization.

20434020557 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 33600, while the sum is 32.

Adding to 20434020557 its reverse (75502043402), we get a palindrome (95936063959).

The spelling of 20434020557 in words is "twenty billion, four hundred thirty-four million, twenty thousand, five hundred fifty-seven".