640927 has 16 divisors (see below), whose sum is σ = 793600. Its totient is φ = 505440.

The previous prime is 640919. The next prime is 640933. The reversal of 640927 is 729046.

It is a cyclic number.

It is not a de Polignac number, because 640927 - 2³ = 640919 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 640895 and 640904.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640907) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8074 + ... + 8152.

It is an arithmetic number, because the mean of its divisors is an integer number (49600).

2⁶⁴⁰⁹²⁷ is an apocalyptic number.

640927 is a deficient number, since it is larger than the sum of its proper divisors (152673).

640927 is a wasteful number, since it uses less digits than its factorization.

640927 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 166.

The product of its (nonzero) digits is 3024, while the sum is 28.

The square root of 640927 is about 800.5791653547. The cubic root of 640927 is about 86.2189750487.

The spelling of 640927 in words is "six hundred forty thousand, nine hundred twenty-seven".