861620166 has 96 divisors (see below), whose sum is σ = 2164046976. Its totient is φ = 254664000.

The previous prime is 861620161. The next prime is 861620171. The reversal of 861620166 is 661026168.

861620166 is a `hidden beast` number, since 8 + 616 + 20 + 16 + 6 = 666.

It is an interprime number because it is at equal distance from previous prime (861620161) and next prime (861620171).

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 861620166.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (861620161) 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 47 ways as a sum of consecutive naturals, for example, 217221 + ... + 221151.

It is an arithmetic number, because the mean of its divisors is an integer number (22542156).

Almost surely, 2^861620166 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 861620166, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1082023488).

861620166 is an abundant number, since it is smaller than the sum of its proper divisors (1302426810).

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

861620166 is a wasteful number, since it uses less digits than its factorization.

861620166 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4000 (or 3988 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 36.

The square root of 861620166 is about 29353.3672003741. The cubic root of 861620166 is about 951.5653476534.

It can be divided in two parts, 8616 and 20166, that added together give a palindrome (28782).

The spelling of 861620166 in words is "eight hundred sixty-one million, six hundred twenty thousand, one hundred sixty-six".