644424263156 has 6 divisors (see below), whose sum is σ = 1127742460530. Its totient is φ = 322212131576.

The previous prime is 644424263143. The next prime is 644424263233. The reversal of 644424263156 is 651362424446.

It can be written as a sum of positive squares in only one way, i.e., 495497735056 + 148926528100 = 703916^2 + 385910^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 644424263156.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80553032891 + ... + 80553032898.

It is an arithmetic number, because the mean of its divisors is an integer number (187957076755).

Almost surely, 2^644424263156 is an apocalyptic number.

It is an amenable number.

644424263156 is a deficient number, since it is larger than the sum of its proper divisors (483318197374).

644424263156 is a wasteful number, since it uses less digits than its factorization.

644424263156 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 161106065793 (or 161106065791 counting only the distinct ones).

The product of its digits is 3317760, while the sum is 47.

The spelling of 644424263156 in words is "six hundred forty-four billion, four hundred twenty-four million, two hundred sixty-three thousand, one hundred fifty-six".