1151511181561 has 4 divisors (see below), whose sum is σ = 1240088964772. Its totient is φ = 1062933398352.

The previous prime is 1151511181523. The next prime is 1151511181571. The reversal of 1151511181561 is 1651811151511.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 560672985961 + 590838195600 = 748781^2 + 768660^2 .

It is a cyclic number.

It is not a de Polignac number, because 1151511181561 - 2²⁷ = 1151376963833 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1151511181561.

It is not an unprimeable number, because it can be changed into a prime (1151511181511) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 44288891586 + ... + 44288891611.

It is an arithmetic number, because the mean of its divisors is an integer number (310022241193).

Almost surely, 2^{1151511181561} is an apocalyptic number.

It is an amenable number.

1151511181561 is a deficient number, since it is larger than the sum of its proper divisors (88577783211).

1151511181561 is an equidigital number, since it uses as much as digits as its factorization.

1151511181561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 88577783210.

The product of its digits is 6000, while the sum is 37.

The spelling of 1151511181561 in words is "one trillion, one hundred fifty-one billion, five hundred eleven million, one hundred eighty-one thousand, five hundred sixty-one".