640703520 has 192 divisors, whose sum is σ = 2271386880. Its totient is φ = 170760960.

The previous prime is 640703519. The next prime is 640703563. The reversal of 640703520 is 25307046.

It is a happy number.

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

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, 349005 + ... + 350835.

It is an arithmetic number, because the mean of its divisors is an integer number (11830140).

Almost surely, 2^640703520 is an apocalyptic number.

640703520 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 640703520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1135693440).

640703520 is an abundant number, since it is smaller than the sum of its proper divisors (1630683360).

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

640703520 is an equidigital number, since it uses as much as digits as its factorization.

640703520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1867 (or 1841 counting only the distinct ones).

The product of its (nonzero) digits is 5040, while the sum is 27.

The square root of 640703520 is about 25312.1219971776. The cubic root of 640703520 is about 862.0895286917.

The spelling of 640703520 in words is "six hundred forty million, seven hundred three thousand, five hundred twenty".