115215261661 has 4 divisors (see below), whose sum is σ = 121992630012. Its totient is φ = 108437893312.

The previous prime is 115215261649. The next prime is 115215261677. The reversal of 115215261661 is 166162512511.

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 56260993636 + 58954268025 = 237194^2 + 242805^2 .

It is a cyclic number.

It is not a de Polignac number, because 115215261661 - 2¹¹ = 115215259613 is a prime.

It is a super-2 number, since 2×115215261661² (a number of 23 digits) contains 22 as substring.

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 115215261661.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (115215261631) 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, 3388684150 + ... + 3388684183.

It is an arithmetic number, because the mean of its divisors is an integer number (30498157503).

Almost surely, 2^115215261661 is an apocalyptic number.

It is an amenable number.

115215261661 is a deficient number, since it is larger than the sum of its proper divisors (6777368351).

115215261661 is an equidigital number, since it uses as much as digits as its factorization.

115215261661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6777368350.

The product of its digits is 21600, while the sum is 37.

The spelling of 115215261661 in words is "one hundred fifteen billion, two hundred fifteen million, two hundred sixty-one thousand, six hundred sixty-one".