15561001117 has 2 divisors, whose sum is σ = 15561001118. Its totient is φ = 15561001116.

The previous prime is 15561001111. The next prime is 15561001147. The reversal of 15561001117 is 71110016551.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14173140601 + 1387860516 = 119051^2 + 37254^2 .

It is a cyclic number.

It is not a de Polignac number, because 15561001117 - 2³ = 15561001109 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (15561001111) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7780500558 + 7780500559.

It is an arithmetic number, because the mean of its divisors is an integer number (7780500559).

Almost surely, 2^15561001117 is an apocalyptic number.

It is an amenable number.

15561001117 is a deficient number, since it is larger than the sum of its proper divisors (1).

15561001117 is an equidigital number, since it uses as much as digits as its factorization.

15561001117 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1050, while the sum is 28.

Adding to 15561001117 its reverse (71110016551), we get a palindrome (86671017668).

The spelling of 15561001117 in words is "fifteen billion, five hundred sixty-one million, one thousand, one hundred seventeen".