640896 has 32 divisors (see below), whose sum is σ = 1703400. Its totient is φ = 213504.

The previous prime is 640891. The next prime is 640901. The reversal of 640896 is 698046.

640896 = T₂₉ + T₃₀ + ... + T₁₅₆.

It is an interprime number because it is at equal distance from previous prime (640891) and next prime (640901).

It is a tau number, because it is divible by the number of its divisors (32).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640891) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 451 + ... + 1218.

2⁶⁴⁰⁸⁹⁶ is an apocalyptic number.

It is an amenable number.

640896 is an abundant number, since it is smaller than the sum of its proper divisors (1062504).

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

640896 is a wasteful number, since it uses less digits than its factorization.

640896 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1686 (or 1674 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 33.

The square root of 640896 is about 800.5598041371. The cubic root of 640896 is about 86.2175849626.

The spelling of 640896 in words is "six hundred forty thousand, eight hundred ninety-six".