661911355661 has 8 divisors (see below), whose sum is σ = 666693924960. Its totient is φ = 657129081168.

The previous prime is 661911355621. The next prime is 661911355697. The reversal of 661911355661 is 166553119166.

661911355661 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 661911355661 - 2⁶ = 661911355597 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661911355621) 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, 6614975 + ... + 6714291.

It is an arithmetic number, because the mean of its divisors is an integer number (83336740620).

Almost surely, 2^661911355661 is an apocalyptic number.

It is an amenable number.

661911355661 is a deficient number, since it is larger than the sum of its proper divisors (4782569299).

661911355661 is a wasteful number, since it uses less digits than its factorization.

661911355661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 147403.

The product of its digits is 874800, while the sum is 50.

The spelling of 661911355661 in words is "six hundred sixty-one billion, nine hundred eleven million, three hundred fifty-five thousand, six hundred sixty-one".