661807711943 has 8 divisors (see below), whose sum is σ = 756356635680. Its totient is φ = 567260029440.

The previous prime is 661807711937. The next prime is 661807711963. The reversal of 661807711943 is 349117708166.

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 661807711943 - 2⁴ = 661807711927 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 (661807711963) 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, 1703663 + ... + 2055743.

It is an arithmetic number, because the mean of its divisors is an integer number (94544579460).

Almost surely, 2^661807711943 is an apocalyptic number.

661807711943 is a deficient number, since it is larger than the sum of its proper divisors (94548923737).

661807711943 is a wasteful number, since it uses less digits than its factorization.

661807711943 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 620617.

The product of its (nonzero) digits is 1524096, while the sum is 53.

The spelling of 661807711943 in words is "six hundred sixty-one billion, eight hundred seven million, seven hundred eleven thousand, nine hundred forty-three".