636679 has 4 divisors (see below), whose sum is σ = 638320. Its totient is φ = 635040.

The previous prime is 636673. The next prime is 636697. The reversal of 636679 is 976636.

636679 = T₆₅₀ + T₆₅₁ + T₆₅₂.

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

It is a cyclic number.

It is not a de Polignac number, because 636679 - 2¹³ = 628487 is a prime.

It is an Ulam number.

It is a Duffinian number.

636679 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (636673) 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 3 ways as a sum of consecutive naturals, for example, 127 + ... + 1135.

It is an arithmetic number, because the mean of its divisors is an integer number (159580).

2⁶³⁶⁶⁷⁹ is an apocalyptic number.

636679 is the 652-nd centered triangular number.

636679 is a deficient number, since it is larger than the sum of its proper divisors (1641).

636679 is a wasteful number, since it uses less digits than its factorization.

636679 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1640.

The product of its digits is 40824, while the sum is 37.

The square root of 636679 is about 797.9216753542. The cubic root of 636679 is about 86.0280690782.

The spelling of 636679 in words is "six hundred thirty-six thousand, six hundred seventy-nine".