640627 has 4 divisors (see below), whose sum is σ = 689920. Its totient is φ = 591336.

The previous prime is 640621. The next prime is 640631. The reversal of 640627 is 726046.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 640627 - 2⁷ = 640499 is a prime.

It is a Duffinian number.

640627 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (640621) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 24627 + ... + 24652.

It is an arithmetic number, because the mean of its divisors is an integer number (172480).

2⁶⁴⁰⁶²⁷ is an apocalyptic number.

640627 is a deficient number, since it is larger than the sum of its proper divisors (49293).

640627 is a wasteful number, since it uses less digits than its factorization.

640627 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 49292.

The product of its (nonzero) digits is 2016, while the sum is 25.

The square root of 640627 is about 800.3917790682. The cubic root of 640627 is about 86.2055207192.

The spelling of 640627 in words is "six hundred forty thousand, six hundred twenty-seven".