1152765121561 has 27 divisors (see below), whose sum is σ = 1236248961367. Its totient is φ = 1074699722240.

The previous prime is 1152765121559. The next prime is 1152765121579. The reversal of 1152765121561 is 1651215672511.

The square root of 1152765121561 is 1073669.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 13 ways, for example, as 352205453961 + 800559667600 = 593469^2 + 894740^2 .

It is not a de Polignac number, because 1152765121561 - 2¹ = 1152765121559 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1152765121961) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 2500574871 + ... + 2500575331.

Almost surely, 2^{1152765121561} is an apocalyptic number.

1152765121561 is the 1073669-th square number.

1152765121561 is the 536835-th centered octagonal number.

It is an amenable number.

1152765121561 is a deficient number, since it is larger than the sum of its proper divisors (83483839806).

1152765121561 is an frugal number, since it uses more digits than its factorization.

1152765121561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1230 (or 615 counting only the distinct ones).

The product of its digits is 126000, while the sum is 43.

The spelling of 1152765121561 in words is "one trillion, one hundred fifty-two billion, seven hundred sixty-five million, one hundred twenty-one thousand, five hundred sixty-one".