661895461188 has 144 divisors (see below), whose sum is σ = 1807107644160. Its totient is φ = 203064288768.

The previous prime is 661895461177. The next prime is 661895461207. The reversal of 661895461188 is 881164598166.

661895461188 is a `hidden beast` number, since 6 + 6 + 1 + 8 + 9 + 5 + 4 + 611 + 8 + 8 = 666.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 332109120 + ... + 332111112.

It is an arithmetic number, because the mean of its divisors is an integer number (12549358640).

Almost surely, 2^661895461188 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 661895461188, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (903553822080).

661895461188 is an abundant number, since it is smaller than the sum of its proper divisors (1145212182972).

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

661895461188 is a wasteful number, since it uses less digits than its factorization.

661895461188 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3738 (or 3733 counting only the distinct ones).

The product of its digits is 19906560, while the sum is 63.

The spelling of 661895461188 in words is "six hundred sixty-one billion, eight hundred ninety-five million, four hundred sixty-one thousand, one hundred eighty-eight".