661252881672768 has 224 divisors, whose sum is σ = 2225791573401600. Its totient is φ = 171753995051520.

The previous prime is 661252881672767. The next prime is 661252881672769. The reversal of 661252881672768 is 867276188252166.

It is an interprime number because it is at equal distance from previous prime (661252881672767) and next prime (661252881672769).

It is a tau number, because it is divible by the number of its divisors (224).

It is a self number, because there is not a number n which added to its sum of digits gives 661252881672768.

It is not an unprimeable number, because it can be changed into a prime (661252881672767) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 455679696 + ... + 457128527.

Almost surely, 2^{661252881672768} is an apocalyptic number.

It is an amenable number.

661252881672768 is an abundant number, since it is smaller than the sum of its proper divisors (1564538691728832).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

661252881672768 is a wasteful number, since it uses less digits than its factorization.

661252881672768 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 912808270 (or 912808246 counting only the distinct ones).

The product of its digits is 1300561920, while the sum is 75.

The spelling of 661252881672768 in words is "six hundred sixty-one trillion, two hundred fifty-two billion, eight hundred eighty-one million, six hundred seventy-two thousand, seven hundred sixty-eight".