661770077166 has 128 divisors (see below), whose sum is σ = 1703565457920. Its totient is φ = 188195212800.

The previous prime is 661770077153. The next prime is 661770077167.

661770077166 is a `hidden beast` number, since 6 + 617 + 7 + 0 + 0 + 7 + 7 + 16 + 6 = 666.

661770077166 is nontrivially palindromic in base 10.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661770077167) 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, 3409576 + ... + 3598436.

It is an arithmetic number, because the mean of its divisors is an integer number (13309105140).

Almost surely, 2^661770077166 is an apocalyptic number.

661770077166 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 661770077166, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (851782728960).

661770077166 is an abundant number, since it is smaller than the sum of its proper divisors (1041795380754).

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

661770077166 is a wasteful number, since it uses less digits than its factorization.

661770077166 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 189247 (or 189241 counting only the distinct ones).

The product of its (nonzero) digits is 3111696, while the sum is 54.

The spelling of 661770077166 in words is "six hundred sixty-one billion, seven hundred seventy million, seventy-seven thousand, one hundred sixty-six".