640087 has 6 divisors (see below), whose sum is σ = 744648. Its totient is φ = 548604.

The previous prime is 640069. The next prime is 640099. The reversal of 640087 is 780046.

640087 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 640087 - 2⁷ = 639959 is a prime.

It is a super-2 number, since 2×640087² = 819422735138, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640007) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 6483 + ... + 6580.

It is an arithmetic number, because the mean of its divisors is an integer number (124108).

2⁶⁴⁰⁰⁸⁷ is an apocalyptic number.

640087 is a deficient number, since it is larger than the sum of its proper divisors (104561).

640087 is a wasteful number, since it uses less digits than its factorization.

640087 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13077 (or 13070 counting only the distinct ones).

The product of its (nonzero) digits is 1344, while the sum is 25.

The square root of 640087 is about 800.0543731522. The cubic root of 640087 is about 86.1812923372.

The spelling of 640087 in words is "six hundred forty thousand, eighty-seven".