644265504541 has 4 divisors (see below), whose sum is σ = 665048262784. Its totient is φ = 623482746300.

The previous prime is 644265504539. The next prime is 644265504593. The reversal of 644265504541 is 145405562446.

644265504541 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 145405562446 = 2 ⋅72702781223.

It is a cyclic number.

It is not a de Polignac number, because 644265504541 - 2¹ = 644265504539 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 644265504491 and 644265504500.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644265504241) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10391379075 + ... + 10391379136.

It is an arithmetic number, because the mean of its divisors is an integer number (166262065696).

Almost surely, 2^644265504541 is an apocalyptic number.

It is an amenable number.

644265504541 is a deficient number, since it is larger than the sum of its proper divisors (20782758243).

644265504541 is a wasteful number, since it uses less digits than its factorization.

644265504541 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20782758242.

The product of its (nonzero) digits is 2304000, while the sum is 46.

The spelling of 644265504541 in words is "six hundred forty-four billion, two hundred sixty-five million, five hundred four thousand, five hundred forty-one".