642447101999 has 4 divisors (see below), whose sum is σ = 642525371520. Its totient is φ = 642368832480.

The previous prime is 642447101969. The next prime is 642447102001. The reversal of 642447101999 is 999101744246.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-642447101999 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (642447101969) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 39122447 + ... + 39138864.

It is an arithmetic number, because the mean of its divisors is an integer number (160631342880).

Almost surely, 2^642447101999 is an apocalyptic number.

642447101999 is a deficient number, since it is larger than the sum of its proper divisors (78269521).

642447101999 is an equidigital number, since it uses as much as digits as its factorization.

642447101999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 78269520.

The product of its (nonzero) digits is 3919104, while the sum is 56.

The spelling of 642447101999 in words is "six hundred forty-two billion, four hundred forty-seven million, one hundred one thousand, nine hundred ninety-nine".