15115506661 has 4 divisors (see below), whose sum is σ = 15152464300. Its totient is φ = 15078549024.

The previous prime is 15115506649. The next prime is 15115506671. The reversal of 15115506661 is 16660551151.

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 9899056036 + 5216450625 = 99494^2 + 72225^2 .

It is a cyclic number.

It is not a de Polignac number, because 15115506661 - 2⁷ = 15115506533 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 15115506661.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (15115506631) 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, 18478206 + ... + 18479023.

It is an arithmetic number, because the mean of its divisors is an integer number (3788116075).

Almost surely, 2^15115506661 is an apocalyptic number.

It is an amenable number.

15115506661 is a deficient number, since it is larger than the sum of its proper divisors (36957639).

15115506661 is an equidigital number, since it uses as much as digits as its factorization.

15115506661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36957638.

The product of its (nonzero) digits is 27000, while the sum is 37.

The spelling of 15115506661 in words is "fifteen billion, one hundred fifteen million, five hundred six thousand, six hundred sixty-one".