644508772053 has 16 divisors (see below), whose sum is σ = 909957499200. Its totient is φ = 404369766656.

The previous prime is 644508772049. The next prime is 644508772129. The reversal of 644508772053 is 350277805446.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 644508772053 - 2² = 644508772049 is a prime.

It is a super-3 number, since 3×644508772053³ (a number of 36 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (51).

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 644508771987 and 644508772005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644508772003) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 323623 + ... + 1180571.

It is an arithmetic number, because the mean of its divisors is an integer number (56872343700).

Almost surely, 2^644508772053 is an apocalyptic number.

It is an amenable number.

644508772053 is a deficient number, since it is larger than the sum of its proper divisors (265448727147).

644508772053 is a wasteful number, since it uses less digits than its factorization.

644508772053 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 871716.

The product of its (nonzero) digits is 5644800, while the sum is 51.

The spelling of 644508772053 in words is "six hundred forty-four billion, five hundred eight million, seven hundred seventy-two thousand, fifty-three".