640077 has 4 divisors (see below), whose sum is σ = 853440. Its totient is φ = 426716.

The previous prime is 640069. The next prime is 640099. The reversal of 640077 is 770046.

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 640077 - 2³ = 640069 is a prime.

It is a D-number.

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 640077.

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 3 ways as a sum of consecutive naturals, for example, 106677 + ... + 106682.

It is an arithmetic number, because the mean of its divisors is an integer number (213360).

2⁶⁴⁰⁰⁷⁷ is an apocalyptic number.

It is an amenable number.

640077 is a deficient number, since it is larger than the sum of its proper divisors (213363).

640077 is a wasteful number, since it uses less digits than its factorization.

640077 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 213362.

The product of its (nonzero) digits is 1176, while the sum is 24.

The square root of 640077 is about 800.0481235526. The cubic root of 640077 is about 86.1808435350.

The spelling of 640077 in words is "six hundred forty thousand, seventy-seven".