156505665553 has 2 divisors, whose sum is σ = 156505665554. Its totient is φ = 156505665552.

The previous prime is 156505665539. The next prime is 156505665623. The reversal of 156505665553 is 355566505651.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 155020950529 + 1484715024 = 393727^2 + 38532^2 .

It is a cyclic number.

It is not a de Polignac number, because 156505665553 - 2¹³ = 156505657361 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 156505665553.

It is not a weakly prime, because it can be changed into another prime (156505665053) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 78252832776 + 78252832777.

It is an arithmetic number, because the mean of its divisors is an integer number (78252832777).

Almost surely, 2^156505665553 is an apocalyptic number.

It is an amenable number.

156505665553 is a deficient number, since it is larger than the sum of its proper divisors (1).

156505665553 is an equidigital number, since it uses as much as digits as its factorization.

156505665553 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 10125000, while the sum is 52.

The spelling of 156505665553 in words is "one hundred fifty-six billion, five hundred five million, six hundred sixty-five thousand, five hundred fifty-three".