861849542009 has 16 divisors (see below), whose sum is σ = 912425417280. Its totient is φ = 811805379840.

The previous prime is 861849541951. The next prime is 861849542023. The reversal of 861849542009 is 900245948168.

It is a cyclic number.

It is not a de Polignac number, because 861849542009 - 2⁸ = 861849541753 is a prime.

It is a super-4 number, since 4×861849542009⁴ (a number of 49 digits) contains 4444 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (861849542809) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2918189 + ... + 3199925.

It is an arithmetic number, because the mean of its divisors is an integer number (57026588580).

Almost surely, 2^861849542009 is an apocalyptic number.

It is an amenable number.

861849542009 is a deficient number, since it is larger than the sum of its proper divisors (50575875271).

861849542009 is a wasteful number, since it uses less digits than its factorization.

861849542009 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 282680.

The product of its (nonzero) digits is 4976640, while the sum is 56.

The spelling of 861849542009 in words is "eight hundred sixty-one billion, eight hundred forty-nine million, five hundred forty-two thousand, nine".