640506240 has 288 divisors, whose sum is σ = 2433740400. Its totient is φ = 155105280.

The previous prime is 640506239. The next prime is 640506241. The reversal of 640506240 is 42605046.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (640506239) and next prime (640506241).

It is a tau number, because it is divible by the number of its divisors (288).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640506241) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 696501 + ... + 697419.

Almost surely, 2^640506240 is an apocalyptic number.

640506240 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 640506240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1216870200).

640506240 is an abundant number, since it is smaller than the sum of its proper divisors (1793234160).

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

640506240 is a wasteful number, since it uses less digits than its factorization.

640506240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 966 (or 940 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 27.

The square root of 640506240 is about 25308.2247500689. The cubic root of 640506240 is about 862.0010371738.

The spelling of 640506240 in words is "six hundred forty million, five hundred six thousand, two hundred forty".