640746 has 12 divisors (see below), whose sum is σ = 1388322. Its totient is φ = 213576.

The previous prime is 640741. The next prime is 640771. The reversal of 640746 is 647046.

It can be written as a sum of positive squares in only one way, i.e., 622521 + 18225 = 789^2 + 135^2 .

It is not an unprimeable number, because it can be changed into a prime (640741) by changing a digit.

640746 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 17781 + ... + 17816.

2⁶⁴⁰⁷⁴⁶ is an apocalyptic number.

640746 is an abundant number, since it is smaller than the sum of its proper divisors (747576).

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

640746 is a wasteful number, since it uses less digits than its factorization.

640746 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35605 (or 35602 counting only the distinct ones).

The product of its (nonzero) digits is 4032, while the sum is 27.

The square root of 640746 is about 800.4661142110. The cubic root of 640746 is about 86.2108581058.

The spelling of 640746 in words is "six hundred forty thousand, seven hundred forty-six".