1661039908164 has 576 divisors, whose sum is σ = 5662626278400. Its totient is φ = 406452695040.

The previous prime is 1661039908123. The next prime is 1661039908247. The reversal of 1661039908164 is 4618099301661.

It is a happy number.

1661039908164 is a `hidden beast` number, since 1 + 6 + 610 + 3 + 9 + 9 + 0 + 8 + 16 + 4 = 666.

It is a self number, because there is not a number n which added to its sum of digits gives 1661039908164.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 193748182 + ... + 193756754.

It is an arithmetic number, because the mean of its divisors is an integer number (9830948400).

Almost surely, 2^{1661039908164} is an apocalyptic number.

1661039908164 is a gapful number since it is divisible by the number (14) 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 1661039908164, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2831313139200).

1661039908164 is an abundant number, since it is smaller than the sum of its proper divisors (4001586370236).

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

1661039908164 is a wasteful number, since it uses less digits than its factorization.

1661039908164 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8705 (or 8686 counting only the distinct ones).

The product of its (nonzero) digits is 1679616, while the sum is 54.

The spelling of 1661039908164 in words is "one trillion, six hundred sixty-one billion, thirty-nine million, nine hundred eight thousand, one hundred sixty-four".