661631566636 has 6 divisors (see below), whose sum is σ = 1157855241620. Its totient is φ = 330815783316.

The previous prime is 661631566633. The next prime is 661631566649. The reversal of 661631566636 is 636665136166.

It is not an unprimeable number, because it can be changed into a prime (661631566633) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82703945826 + ... + 82703945833.

Almost surely, 2^661631566636 is an apocalyptic number.

It is an amenable number.

661631566636 is a deficient number, since it is larger than the sum of its proper divisors (496223674984).

661631566636 is a wasteful number, since it uses less digits than its factorization.

661631566636 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 165407891663 (or 165407891661 counting only the distinct ones).

The product of its digits is 12597120, while the sum is 55.

The spelling of 661631566636 in words is "six hundred sixty-one billion, six hundred thirty-one million, five hundred sixty-six thousand, six hundred thirty-six".