661681290743 has 8 divisors (see below), whose sum is σ = 721910933136. Its totient is φ = 601464448000.

The previous prime is 661681290719. The next prime is 661681290749. The reversal of 661681290743 is 347092186166.

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 661681290743 - 2⁶ = 661681290679 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 (661681290749) 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, 3091658 + ... + 3298743.

It is an arithmetic number, because the mean of its divisors is an integer number (90238866642).

Almost surely, 2^661681290743 is an apocalyptic number.

661681290743 is a deficient number, since it is larger than the sum of its proper divisors (60229642393).

661681290743 is a wasteful number, since it uses less digits than its factorization.

661681290743 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6399825.

The product of its (nonzero) digits is 2612736, while the sum is 53.

The spelling of 661681290743 in words is "six hundred sixty-one billion, six hundred eighty-one million, two hundred ninety thousand, seven hundred forty-three".