644557342602 has 32 divisors (see below), whose sum is σ = 1338667352064. Its totient is φ = 206676673200.

The previous prime is 644557342591. The next prime is 644557342609. The reversal of 644557342602 is 206243755446.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (644557342609) 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 15 ways as a sum of consecutive naturals, for example, 10344274 + ... + 10406397.

It is an arithmetic number, because the mean of its divisors is an integer number (41833354752).

Almost surely, 2^644557342602 is an apocalyptic number.

644557342602 is a gapful number since it is divisible by the number (62) formed by its first and last digit.

644557342602 is an abundant number, since it is smaller than the sum of its proper divisors (694110009462).

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

644557342602 is a wasteful number, since it uses less digits than its factorization.

644557342602 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20750874.

The product of its (nonzero) digits is 4838400, while the sum is 48.

The spelling of 644557342602 in words is "six hundred forty-four billion, five hundred fifty-seven million, three hundred forty-two thousand, six hundred two".