661183872687668 has 48 divisors (see below), whose sum is σ = 1297154804434944. Its totient is φ = 292239634631040.

The previous prime is 661183872687643. The next prime is 661183872687703. The reversal of 661183872687668 is 866786278381166.

It is a super-2 number, since 2×661183872687668² (a number of 30 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 119401055 + ... + 124815782.

It is an arithmetic number, because the mean of its divisors is an integer number (27024058425728).

Almost surely, 2^{661183872687668} is an apocalyptic number.

It is an amenable number.

661183872687668 is a deficient number, since it is larger than the sum of its proper divisors (635970931747276).

661183872687668 is a wasteful number, since it uses less digits than its factorization.

661183872687668 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 244218552 (or 244218550 counting only the distinct ones).

The product of its digits is 9364045824, while the sum is 83.

The spelling of 661183872687668 in words is "six hundred sixty-one trillion, one hundred eighty-three billion, eight hundred seventy-two million, six hundred eighty-seven thousand, six hundred sixty-eight".