861555461617 has 4 divisors (see below), whose sum is σ = 861626075760. Its totient is φ = 861484847476.

The previous prime is 861555461597. The next prime is 861555461707. The reversal of 861555461617 is 716164555168.

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-861555461617 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (861555461917) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 35288767 + ... + 35313172.

It is an arithmetic number, because the mean of its divisors is an integer number (215406518940).

Almost surely, 2^861555461617 is an apocalyptic number.

It is an amenable number.

861555461617 is a deficient number, since it is larger than the sum of its proper divisors (70614143).

861555461617 is a wasteful number, since it uses less digits than its factorization.

861555461617 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 70614142.

The product of its digits is 6048000, while the sum is 55.

The spelling of 861555461617 in words is "eight hundred sixty-one billion, five hundred fifty-five million, four hundred sixty-one thousand, six hundred seventeen".