1165115521 has 2 divisors, whose sum is σ = 1165115522. Its totient is φ = 1165115520.

The previous prime is 1165115509. The next prime is 1165115537. The reversal of 1165115521 is 1255115611.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 831687921 + 333427600 = 28839^2 + 18260^2 .

It is a cyclic number.

It is not a de Polignac number, because 1165115521 - 2¹³ = 1165107329 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1165115521.

It is not a weakly prime, because it can be changed into another prime (1165115561) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 582557760 + 582557761.

It is an arithmetic number, because the mean of its divisors is an integer number (582557761).

Almost surely, 2^1165115521 is an apocalyptic number.

It is an amenable number.

1165115521 is a deficient number, since it is larger than the sum of its proper divisors (1).

1165115521 is an equidigital number, since it uses as much as digits as its factorization.

1165115521 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1500, while the sum is 28.

The square root of 1165115521 is about 34133.7885532796. The cubic root of 1165115521 is about 1052.2598406013.

It can be divided in two parts, 11651 and 15521, that added together give a palindrome (27172).

The spelling of 1165115521 in words is "one billion, one hundred sixty-five million, one hundred fifteen thousand, five hundred twenty-one".