661771240320832 has 14 divisors (see below), whose sum is σ = 1313202305011778. Its totient is φ = 330885620160384.

The previous prime is 661771240320793. The next prime is 661771240320847. The reversal of 661771240320832 is 238023042177166.

It can be written as a sum of positive squares in only one way, i.e., 615858473718016 + 45912766602816 = 24816496^2 + 6775896^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 661771240320832.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5170087814943 + ... + 5170087815070.

Almost surely, 2^{661771240320832} is an apocalyptic number.

It is an amenable number.

661771240320832 is a deficient number, since it is larger than the sum of its proper divisors (651431064690946).

661771240320832 is a wasteful number, since it uses less digits than its factorization.

661771240320832 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10340175630025 (or 10340175630015 counting only the distinct ones).

The product of its (nonzero) digits is 4064256, while the sum is 52.

Adding to 661771240320832 its reverse (238023042177166), we get a palindrome (899794282497998).

The spelling of 661771240320832 in words is "six hundred sixty-one trillion, seven hundred seventy-one billion, two hundred forty million, three hundred twenty thousand, eight hundred thirty-two".