640037 has 4 divisors (see below), whose sum is σ = 646476. Its totient is φ = 633600.

The previous prime is 640027. The next prime is 640039. The reversal of 640037 is 730046.

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

It can be written as a sum of positive squares in 2 ways, for example, as 454276 + 185761 = 674^2 + 431^2 .

It is a cyclic number.

It is not a de Polignac number, because 640037 - 2¹⁴ = 623653 is a prime.

It is a super-2 number, since 2×640037² = 819294722738, which contains 22 as substring.

It is a Duffinian number.

It is a nialpdrome in base 15.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 640037.

It is not an unprimeable number, because it can be changed into a prime (640039) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3068 + ... + 3269.

It is an arithmetic number, because the mean of its divisors is an integer number (161619).

2⁶⁴⁰⁰³⁷ is an apocalyptic number.

It is an amenable number.

640037 is a deficient number, since it is larger than the sum of its proper divisors (6439).

640037 is a wasteful number, since it uses less digits than its factorization.

640037 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6438.

The product of its (nonzero) digits is 504, while the sum is 20.

The square root of 640037 is about 800.0231246658. The cubic root of 640037 is about 86.1790482793.

Subtracting 640037 from its reverse (730046), we obtain a palindrome (90009).

The spelling of 640037 in words is "six hundred forty thousand, thirty-seven".