640277 has 4 divisors (see below), whose sum is σ = 698496. Its totient is φ = 582060.

The previous prime is 640267. The next prime is 640279. The reversal of 640277 is 772046.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 640277 - 2⁴ = 640261 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640279) 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, 29093 + ... + 29114.

It is an arithmetic number, because the mean of its divisors is an integer number (174624).

2⁶⁴⁰²⁷⁷ is an apocalyptic number.

It is an amenable number.

640277 is a deficient number, since it is larger than the sum of its proper divisors (58219).

640277 is a wasteful number, since it uses less digits than its factorization.

640277 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 58218.

The product of its (nonzero) digits is 2352, while the sum is 26.

The square root of 640277 is about 800.1731062714. The cubic root of 640277 is about 86.1898186915.

Subtracting 640277 from its reverse (772046), we obtain a square (131769 = 363²).

The spelling of 640277 in words is "six hundred forty thousand, two hundred seventy-seven".