639786240 has 432 divisors, whose sum is σ = 2423366400. Its totient is φ = 155271168.

The previous prime is 639786229. The next prime is 639786253. The reversal of 639786240 is 42687936.

639786240 = T₃₉₈₅ + T₃₉₈₆ + ... + T₄₀₆₃.

639786240 is a `hidden beast` number, since 639 + 7 + 8 + 6 + 2 + 4 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 8098521 + ... + 8098599.

Almost surely, 2^639786240 is an apocalyptic number.

639786240 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 639786240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1211683200).

639786240 is an abundant number, since it is smaller than the sum of its proper divisors (1783580160).

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

639786240 is a wasteful number, since it uses less digits than its factorization.

639786240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 162 (or 145 counting only the distinct ones).

The product of its (nonzero) digits is 435456, while the sum is 45.

The square root of 639786240 is about 25293.9961255631. The cubic root of 639786240 is about 861.6779211708.

The spelling of 639786240 in words is "six hundred thirty-nine million, seven hundred eighty-six thousand, two hundred forty".