661867684996 has 24 divisors (see below), whose sum is σ = 1336841666496. Its totient is φ = 280849087200.

The previous prime is 661867684991. The next prime is 661867684997. The reversal of 661867684996 is 699486768166.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (661867684991) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 117017626 + ... + 117023281.

It is an arithmetic number, because the mean of its divisors is an integer number (55701736104).

Almost surely, 2^661867684996 is an apocalyptic number.

It is an amenable number.

661867684996 is an abundant number, since it is smaller than the sum of its proper divisors (674973981500).

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

661867684996 is a wasteful number, since it uses less digits than its factorization.

661867684996 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 234041019 (or 234041017 counting only the distinct ones).

The product of its digits is 1128701952, while the sum is 76.

The spelling of 661867684996 in words is "six hundred sixty-one billion, eight hundred sixty-seven million, six hundred eighty-four thousand, nine hundred ninety-six".