7861393561 has 4 divisors (see below), whose sum is σ = 8984449792. Its totient is φ = 6738337332.

The previous prime is 7861393549. The next prime is 7861393609. The reversal of 7861393561 is 1653931687.

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-7861393561 is a prime.

It is the 88665-th Hogben number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (7861393511) by changing a digit.

It is a nontrivial repunit in base 88664.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 561528105 + ... + 561528118.

It is an arithmetic number, because the mean of its divisors is an integer number (2246112448).

Almost surely, 2^7861393561 is an apocalyptic number.

It is an amenable number.

7861393561 is a deficient number, since it is larger than the sum of its proper divisors (1123056231).

7861393561 is a wasteful number, since it uses less digits than its factorization.

7861393561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1123056230.

The product of its digits is 816480, while the sum is 49.

The square root of 7861393561 is about 88664.5000042294. The cubic root of 7861393561 is about 1988.3821063680.

The spelling of 7861393561 in words is "seven billion, eight hundred sixty-one million, three hundred ninety-three thousand, five hundred sixty-one".