661444074721 has 8 divisors (see below), whose sum is σ = 666995503104. Its totient is φ = 655915729920.

The previous prime is 661444074689. The next prime is 661444074737. The reversal of 661444074721 is 127470444166.

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 661444074721 - 2⁵ = 661444074689 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (661444774721) 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, 5713345 + ... + 5827966.

It is an arithmetic number, because the mean of its divisors is an integer number (83374437888).

Almost surely, 2^661444074721 is an apocalyptic number.

It is an amenable number.

661444074721 is a deficient number, since it is larger than the sum of its proper divisors (5551428383).

661444074721 is a wasteful number, since it uses less digits than its factorization.

661444074721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11541791.

The product of its (nonzero) digits is 903168, while the sum is 46.

The spelling of 661444074721 in words is "six hundred sixty-one billion, four hundred forty-four million, seventy-four thousand, seven hundred twenty-one".