640355896 has 8 divisors (see below), whose sum is σ = 1200667320. Its totient is φ = 320177944.

The previous prime is 640355869. The next prime is 640355897. The reversal of 640355896 is 698553046.

It is a tau number, because it is divible by the number of its divisors (8).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640355897) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40022236 + ... + 40022251.

It is an arithmetic number, because the mean of its divisors is an integer number (150083415).

Almost surely, 2^640355896 is an apocalyptic number.

It is an amenable number.

640355896 is a deficient number, since it is larger than the sum of its proper divisors (560311424).

640355896 is a wasteful number, since it uses less digits than its factorization.

640355896 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 80044493 (or 80044489 counting only the distinct ones).

The product of its (nonzero) digits is 777600, while the sum is 46.

The square root of 640355896 is about 25305.2543160506. The cubic root of 640355896 is about 861.9335869721.

The spelling of 640355896 in words is "six hundred forty million, three hundred fifty-five thousand, eight hundred ninety-six".