661994499166 has 128 divisors (see below), whose sum is σ = 1343857213440. Its totient is φ = 237597235200.

The previous prime is 661994499151. The next prime is 661994499209.

661994499166 is nontrivially palindromic in base 10.

661994499166 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a junction number, because it is equal to n+sod(n) for n = 661994499095 and 661994499104.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 195219331 + ... + 195222721.

It is an arithmetic number, because the mean of its divisors is an integer number (10498884480).

Almost surely, 2^661994499166 is an apocalyptic number.

661994499166 is an abundant number, since it is smaller than the sum of its proper divisors (681862714274).

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

661994499166 is a wasteful number, since it uses less digits than its factorization.

661994499166 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4027 (or 4001 counting only the distinct ones).

The product of its digits is 136048896, while the sum is 70.

The spelling of 661994499166 in words is "six hundred sixty-one billion, nine hundred ninety-four million, four hundred ninety-nine thousand, one hundred sixty-six".