155971565557 has 2 divisors, whose sum is σ = 155971565558. Its totient is φ = 155971565556.

The previous prime is 155971565551. The next prime is 155971565569. The reversal of 155971565557 is 755565179551.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 154186587556 + 1784978001 = 392666^2 + 42249^2 .

It is a cyclic number.

It is not a de Polignac number, because 155971565557 - 2³ = 155971565549 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 155971565495 and 155971565504.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (155971565551) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 77985782778 + 77985782779.

It is an arithmetic number, because the mean of its divisors is an integer number (77985782779).

Almost surely, 2^155971565557 is an apocalyptic number.

It is an amenable number.

155971565557 is a deficient number, since it is larger than the sum of its proper divisors (1).

155971565557 is an equidigital number, since it uses as much as digits as its factorization.

155971565557 is an evil number, because the sum of its binary digits is even.

The product of its digits is 41343750, while the sum is 61.

The spelling of 155971565557 in words is "one hundred fifty-five billion, nine hundred seventy-one million, five hundred sixty-five thousand, five hundred fifty-seven".