861999552516960 has 1920 divisors, whose sum is σ = 3646448315427456. Its totient is φ = 188993995407360.

The previous prime is 861999552516943. The next prime is 861999552516989. The reversal of 861999552516960 is 69615255999168.

861999552516960 is a `hidden beast` number, since 8 + 6 + 1 + 9 + 9 + 9 + 5 + 5 + 2 + 516 + 96 + 0 = 666.

It is a super-3 number, since 3×861999552516960³ (a number of 46 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (81).

It is a self number, because there is not a number n which added to its sum of digits gives 861999552516960.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 319 ways as a sum of consecutive naturals, for example, 75927022644 + ... + 75927033996.

Almost surely, 2^{861999552516960} is an apocalyptic number.

861999552516960 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 861999552516960, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1823224157713728).

861999552516960 is an abundant number, since it is smaller than the sum of its proper divisors (2784448762910496).

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

861999552516960 is a wasteful number, since it uses less digits than its factorization.

861999552516960 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12230 (or 12213 counting only the distinct ones).

The product of its (nonzero) digits is 2834352000, while the sum is 81.

The spelling of 861999552516960 in words is "eight hundred sixty-one trillion, nine hundred ninety-nine billion, five hundred fifty-two million, five hundred sixteen thousand, nine hundred sixty".