642664043667 has 12 divisors (see below), whose sum is σ = 929343812904. Its totient is φ = 427957477920.

The previous prime is 642664043657. The next prime is 642664043711. The reversal of 642664043667 is 766340466246.

It is not a de Polignac number, because 642664043667 - 2¹² = 642664039571 is a prime.

It is not an unprimeable number, because it can be changed into a prime (642664043657) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 40426434 + ... + 40442327.

It is an arithmetic number, because the mean of its divisors is an integer number (77445317742).

Almost surely, 2^642664043667 is an apocalyptic number.

642664043667 is a deficient number, since it is larger than the sum of its proper divisors (286679769237).

642664043667 is a wasteful number, since it uses less digits than its factorization.

642664043667 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 80869650 (or 80869647 counting only the distinct ones).

The product of its (nonzero) digits is 20901888, while the sum is 54.

The spelling of 642664043667 in words is "six hundred forty-two billion, six hundred sixty-four million, forty-three thousand, six hundred sixty-seven".