640006356 has 24 divisors (see below), whose sum is σ = 1629107424. Its totient is φ = 193941280.

The previous prime is 640006343. The next prime is 640006357. The reversal of 640006356 is 653600046.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640006357) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2424135 + ... + 2424398.

It is an arithmetic number, because the mean of its divisors is an integer number (67879476).

Almost surely, 2^640006356 is an apocalyptic number.

640006356 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

It is an amenable number.

640006356 is an abundant number, since it is smaller than the sum of its proper divisors (989101068).

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

640006356 is a wasteful number, since it uses less digits than its factorization.

640006356 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4848551 (or 4848549 counting only the distinct ones).

The product of its (nonzero) digits is 12960, while the sum is 30.

The square root of 640006356 is about 25298.3469025152. The cubic root of 640006356 is about 861.7767288339.

The spelling of 640006356 in words is "six hundred forty million, six thousand, three hundred fifty-six".