640446 has 16 divisors (see below), whose sum is σ = 1290384. Its totient is φ = 211904.

The previous prime is 640421. The next prime is 640457. The reversal of 640446 is 644046.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 730 + ... + 1346.

It is an arithmetic number, because the mean of its divisors is an integer number (80649).

2⁶⁴⁰⁴⁴⁶ is an apocalyptic number.

640446 is an abundant number, since it is smaller than the sum of its proper divisors (649938).

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

640446 is a wasteful number, since it uses less digits than its factorization.

640446 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 795.

The product of its (nonzero) digits is 2304, while the sum is 24.

The square root of 640446 is about 800.2787014534. The cubic root of 640446 is about 86.1974012420.

Subtracting 640446 from its reverse (644046), we obtain a square (3600 = 60²).

The spelling of 640446 in words is "six hundred forty thousand, four hundred forty-six".