661282739885 has 16 divisors (see below), whose sum is σ = 800705133360. Its totient is φ = 524250639360.

The previous prime is 661282739731. The next prime is 661282739903. The reversal of 661282739885 is 588937282166.

It can be written as a sum of positive squares in 8 ways, for example, as 4933236169 + 656349503716 = 70237^2 + 810154^2 .

It is not a de Polignac number, because 661282739885 - 2⁸ = 661282739629 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3141731 + ... + 3345599.

It is an arithmetic number, because the mean of its divisors is an integer number (50044070835).

Almost surely, 2^661282739885 is an apocalyptic number.

It is an amenable number.

661282739885 is a deficient number, since it is larger than the sum of its proper divisors (139422393475).

661282739885 is a wasteful number, since it uses less digits than its factorization.

661282739885 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 209728.

The product of its digits is 69672960, while the sum is 65.

The spelling of 661282739885 in words is "six hundred sixty-one billion, two hundred eighty-two million, seven hundred thirty-nine thousand, eight hundred eighty-five".