8115661261 has 4 divisors (see below), whose sum is σ = 8117536000. Its totient is φ = 8113786524.

The previous prime is 8115661217. The next prime is 8115661271. The reversal of 8115661261 is 1621665118.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 8115661261 - 2¹¹ = 8115659213 is a prime.

It is a super-2 number, since 2×8115661261² (a number of 21 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 8115661261.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (8115661271) 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, 930861 + ... + 939538.

It is an arithmetic number, because the mean of its divisors is an integer number (2029384000).

Almost surely, 2^8115661261 is an apocalyptic number.

It is an amenable number.

8115661261 is a deficient number, since it is larger than the sum of its proper divisors (1874739).

8115661261 is a wasteful number, since it uses less digits than its factorization.

8115661261 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1874738.

The product of its digits is 17280, while the sum is 37.

The square root of 8115661261 is about 90086.9649893923. The cubic root of 8115661261 is about 2009.5923581967.

The spelling of 8115661261 in words is "eight billion, one hundred fifteen million, six hundred sixty-one thousand, two hundred sixty-one".