861635546879 has 4 divisors (see below), whose sum is σ = 863434368960. Its totient is φ = 859836724800.

The previous prime is 861635546867. The next prime is 861635546899. The reversal of 861635546879 is 978645536168.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-861635546879 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (861635546809) 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, 899410322 + ... + 899411279.

It is an arithmetic number, because the mean of its divisors is an integer number (215858592240).

Almost surely, 2^861635546879 is an apocalyptic number.

861635546879 is a deficient number, since it is larger than the sum of its proper divisors (1798822081).

861635546879 is a wasteful number, since it uses less digits than its factorization.

861635546879 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1798822080.

The product of its digits is 261273600, while the sum is 68.

The spelling of 861635546879 in words is "eight hundred sixty-one billion, six hundred thirty-five million, five hundred forty-six thousand, eight hundred seventy-nine".