861799156992 has 576 divisors, whose sum is σ = 2737975609600. Its totient is φ = 266588651520.

The previous prime is 861799156979. The next prime is 861799156997. The reversal of 861799156992 is 299651997168.

It is a tau number, because it is divible by the number of its divisors (576).

It is a Harshad number since it is a multiple of its sum of digits (72).

It is a self number, because there is not a number n which added to its sum of digits gives 861799156992.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (861799156997) 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 63 ways as a sum of consecutive naturals, for example, 2310453318 + ... + 2310453690.

Almost surely, 2^861799156992 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 861799156992, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1368987804800).

861799156992 is an abundant number, since it is smaller than the sum of its proper divisors (1876176452608).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

861799156992 is a wasteful number, since it uses less digits than its factorization.

861799156992 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 731 (or 711 counting only the distinct ones).

The product of its digits is 132269760, while the sum is 72.

The spelling of 861799156992 in words is "eight hundred sixty-one billion, seven hundred ninety-nine million, one hundred fifty-six thousand, nine hundred ninety-two".