661256966616 has 32 divisors (see below), whose sum is σ = 1653162786240. Its totient is φ = 220416272928.

The previous prime is 661256966561. The next prime is 661256966647. The reversal of 661256966616 is 616669652166.

It is a self number, because there is not a number n which added to its sum of digits gives 661256966616.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3118815 + ... + 3324081.

It is an arithmetic number, because the mean of its divisors is an integer number (51661337070).

Almost surely, 2^661256966616 is an apocalyptic number.

It is an amenable number.

661256966616 is an abundant number, since it is smaller than the sum of its proper divisors (991905819624).

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

661256966616 is a wasteful number, since it uses less digits than its factorization.

661256966616 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 339503 (or 339499 counting only the distinct ones).

The product of its digits is 25194240, while the sum is 60.

The spelling of 661256966616 in words is "six hundred sixty-one billion, two hundred fifty-six million, nine hundred sixty-six thousand, six hundred sixteen".