640371 has 8 divisors (see below), whose sum is σ = 861840. Its totient is φ = 422912.

The previous prime is 640369. The next prime is 640411. The reversal of 640371 is 173046.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 640371 - 2¹ = 640369 is a prime.

It is not an unprimeable number, because it can be changed into a prime (640771) 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 7 ways as a sum of consecutive naturals, for example, 606 + ... + 1283.

It is an arithmetic number, because the mean of its divisors is an integer number (107730).

2⁶⁴⁰³⁷¹ is an apocalyptic number.

640371 is a deficient number, since it is larger than the sum of its proper divisors (221469).

640371 is a wasteful number, since it uses less digits than its factorization.

640371 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2005.

The product of its (nonzero) digits is 504, while the sum is 21.

The square root of 640371 is about 800.2318414060. The cubic root of 640371 is about 86.1940363695.

The spelling of 640371 in words is "six hundred forty thousand, three hundred seventy-one".