639690240 has 320 divisors, whose sum is σ = 2383704576. Its totient is φ = 143327232.

The previous prime is 639690221. The next prime is 639690277. The reversal of 639690240 is 42096936.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (320).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3924399 + ... + 3924561.

Almost surely, 2^639690240 is an apocalyptic number.

639690240 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 639690240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1191852288).

639690240 is an abundant number, since it is smaller than the sum of its proper divisors (1744014336).

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

639690240 is a wasteful number, since it uses less digits than its factorization.

639690240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 269 (or 253 counting only the distinct ones).

The product of its (nonzero) digits is 69984, while the sum is 39.

The square root of 639690240 is about 25292.0983708351. The cubic root of 639690240 is about 861.6348207241.

The spelling of 639690240 in words is "six hundred thirty-nine million, six hundred ninety thousand, two hundred forty".