661343631751 has 8 divisors (see below), whose sum is σ = 746343910800. Its totient is φ = 580489707840.

The previous prime is 661343631749. The next prime is 661343631763. The reversal of 661343631751 is 157136343166.

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 661343631751 - 2¹ = 661343631749 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 (661343631701) 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, 1036588446 + ... + 1036589083.

It is an arithmetic number, because the mean of its divisors is an integer number (93292988850).

Almost surely, 2^661343631751 is an apocalyptic number.

661343631751 is a deficient number, since it is larger than the sum of its proper divisors (85000279049).

661343631751 is a wasteful number, since it uses less digits than its factorization.

661343631751 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2073177569.

The product of its digits is 816480, while the sum is 46.

The spelling of 661343631751 in words is "six hundred sixty-one billion, three hundred forty-three million, six hundred thirty-one thousand, seven hundred fifty-one".