644536363131 has 12 divisors (see below), whose sum is σ = 965478338552. Its totient is φ = 429690908592.

The previous prime is 644536363109. The next prime is 644536363147. The reversal of 644536363131 is 131363635446.

It is a happy number.

644536363131 is a `hidden beast` number, since 6 + 4 + 4 + 5 + 3 + 6 + 3 + 631 + 3 + 1 = 666.

It is not a de Polignac number, because 644536363131 - 2⁶ = 644536363067 is a prime.

It is a super-2 number, since 2×644536363131² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (644536363181) 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 11 ways as a sum of consecutive naturals, for example, 1326206266 + ... + 1326206751.

Almost surely, 2^644536363131 is an apocalyptic number.

644536363131 is a deficient number, since it is larger than the sum of its proper divisors (320941975421).

644536363131 is an equidigital number, since it uses as much as digits as its factorization.

644536363131 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2652413032 (or 2652413020 counting only the distinct ones).

The product of its digits is 1399680, while the sum is 45.

Adding to 644536363131 its reverse (131363635446), we get a palindrome (775899998577).

The spelling of 644536363131 in words is "six hundred forty-four billion, five hundred thirty-six million, three hundred sixty-three thousand, one hundred thirty-one".