644169770496 has 600 divisors, whose sum is σ = 2271497271120. Its totient is φ = 178034319360.

The previous prime is 644169770479. The next prime is 644169770509. The reversal of 644169770496 is 694077961446.

644169770496 is a `hidden beast` number, since 6 + 44 + 16 + 97 + 7 + 0 + 496 = 666.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 278980990 + ... + 278983298.

Almost surely, 2^644169770496 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 644169770496, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1135748635560).

644169770496 is an abundant number, since it is smaller than the sum of its proper divisors (1627327500624).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

644169770496 is an equidigital number, since it uses as much as digits as its factorization.

644169770496 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2408 (or 2352 counting only the distinct ones).

The product of its (nonzero) digits is 54867456, while the sum is 63.

The spelling of 644169770496 in words is "six hundred forty-four billion, one hundred sixty-nine million, seven hundred seventy thousand, four hundred ninety-six".