640241642661 has 16 divisors (see below), whose sum is σ = 894813057600. Its totient is φ = 406733201280.

The previous prime is 640241642627. The next prime is 640241642681. The reversal of 640241642661 is 166246142046.

It is not a de Polignac number, because 640241642661 - 2¹⁷ = 640241511589 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640241642681) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 60520486 + ... + 60531063.

It is an arithmetic number, because the mean of its divisors is an integer number (55925816100).

Almost surely, 2^640241642661 is an apocalyptic number.

It is an amenable number.

640241642661 is a deficient number, since it is larger than the sum of its proper divisors (254571414939).

640241642661 is a wasteful number, since it uses less digits than its factorization.

640241642661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 121051636.

The product of its (nonzero) digits is 331776, while the sum is 42.

The spelling of 640241642661 in words is "six hundred forty billion, two hundred forty-one million, six hundred forty-two thousand, six hundred sixty-one".