8138615861 has 4 divisors (see below), whose sum is σ = 8154177792. Its totient is φ = 8123053932.

The previous prime is 8138615851. The next prime is 8138615869. The reversal of 8138615861 is 1685168318.

It is a happy number.

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 a de Polignac number, because none of the positive numbers 2^k-8138615861 is a prime.

It is a super-3 number, since 3×8138615861³ (a number of 31 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (8138615869) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7780181 + ... + 7781226.

It is an arithmetic number, because the mean of its divisors is an integer number (2038544448).

Almost surely, 2^8138615861 is an apocalyptic number.

It is an amenable number.

8138615861 is a deficient number, since it is larger than the sum of its proper divisors (15561931).

8138615861 is a wasteful number, since it uses less digits than its factorization.

8138615861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15561930.

The product of its digits is 276480, while the sum is 47.

The square root of 8138615861 is about 90214.2774786785. The cubic root of 8138615861 is about 2011.4852401274.

The spelling of 8138615861 in words is "eight billion, one hundred thirty-eight million, six hundred fifteen thousand, eight hundred sixty-one".