642445161605 has 16 divisors (see below), whose sum is σ = 830427742704. Its totient is φ = 474311946240.

The previous prime is 642445161599. The next prime is 642445161607. The reversal of 642445161605 is 506161544246.

It can be written as a sum of positive squares in 8 ways, for example, as 15177993601 + 627267168004 = 123199^2 + 792002^2 .

It is not a de Polignac number, because 642445161605 - 2⁸ = 642445161349 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 (642445161607) 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 15 ways as a sum of consecutive naturals, for example, 851036 + ... + 1417445.

It is an arithmetic number, because the mean of its divisors is an integer number (51901733919).

Almost surely, 2^642445161605 is an apocalyptic number.

642445161605 is a gapful number since it is divisible by the number (65) formed by its first and last digit.

It is an amenable number.

642445161605 is a deficient number, since it is larger than the sum of its proper divisors (187982581099).

642445161605 is a wasteful number, since it uses less digits than its factorization.

642445161605 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2272856.

The product of its (nonzero) digits is 691200, while the sum is 44.

The spelling of 642445161605 in words is "six hundred forty-two billion, four hundred forty-five million, one hundred sixty-one thousand, six hundred five".