644046120 has 128 divisors (see below), whose sum is σ = 2166912000. Its totient is φ = 170138880.

The previous prime is 644046119. The next prime is 644046121. The reversal of 644046120 is 21640446.

644046120 is a `hidden beast` number, since 6 + 4 + 40 + 4 + 612 + 0 = 666.

It is an interprime number because it is at equal distance from previous prime (644046119) and next prime (644046121).

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (644046121) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 114985 + ... + 120455.

It is an arithmetic number, because the mean of its divisors is an integer number (16929000).

Almost surely, 2^644046120 is an apocalyptic number.

644046120 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 644046120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1083456000).

644046120 is an abundant number, since it is smaller than the sum of its proper divisors (1522865880).

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

644046120 is a wasteful number, since it uses less digits than its factorization.

644046120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5600 (or 5590 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 27.

The square root of 644046120 is about 25378.0637559291. The cubic root of 644046120 is about 863.5861250790.

Adding to 644046120 its reverse (21640446), we get a palindrome (665686566).

The spelling of 644046120 in words is "six hundred forty-four million, forty-six thousand, one hundred twenty".