644137824362 has 4 divisors (see below), whose sum is σ = 966206736546. Its totient is φ = 322068912180.

The previous prime is 644137824361. The next prime is 644137824401. The reversal of 644137824362 is 263428731446.

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

It can be written as a sum of positive squares in only one way, i.e., 508042498441 + 136095325921 = 712771^2 + 368911^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 644137824362.

It is not an unprimeable number, because it can be changed into a prime (644137824361) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 161034456089 + ... + 161034456092.

Almost surely, 2^644137824362 is an apocalyptic number.

644137824362 is a deficient number, since it is larger than the sum of its proper divisors (322068912184).

644137824362 is a wasteful number, since it uses less digits than its factorization.

644137824362 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 322068912183.

The product of its digits is 4644864, while the sum is 50.

The spelling of 644137824362 in words is "six hundred forty-four billion, one hundred thirty-seven million, eight hundred twenty-four thousand, three hundred sixty-two".