644807061042 has 64 divisors (see below), whose sum is σ = 1354987146240. Its totient is φ = 204350371776.

The previous prime is 644807061029. The next prime is 644807061061. The reversal of 644807061042 is 240160708446.

It is a super-2 number, since 2×644807061042² (a number of 24 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 644807060985 and 644807061003.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2039973 + ... + 2334759.

It is an arithmetic number, because the mean of its divisors is an integer number (21171674160).

Almost surely, 2^644807061042 is an apocalyptic number.

644807061042 is an abundant number, since it is smaller than the sum of its proper divisors (710180085198).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

644807061042 is a wasteful number, since it uses less digits than its factorization.

644807061042 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 295055.

The product of its (nonzero) digits is 258048, while the sum is 42.

Adding to 644807061042 its reverse (240160708446), we get a palindrome (884967769488).

The spelling of 644807061042 in words is "six hundred forty-four billion, eight hundred seven million, sixty-one thousand, forty-two".