636399 has 12 divisors (see below), whose sum is σ = 949312. Its totient is φ = 410400.

The previous prime is 636359. The next prime is 636403. The reversal of 636399 is 993636.

636399 = 128² + 129² + ... + 158².

It is not a de Polignac number, because 636399 - 2¹³ = 628207 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 (636319) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 862 + ... + 1419.

2⁶³⁶³⁹⁹ is an apocalyptic number.

636399 is a deficient number, since it is larger than the sum of its proper divisors (312913).

636399 is a wasteful number, since it uses less digits than its factorization.

636399 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2318 (or 2315 counting only the distinct ones).

The product of its digits is 26244, while the sum is 36.

The square root of 636399 is about 797.7462002417. The cubic root of 636399 is about 86.0154560286.

It can be divided in two parts, 636 and 399, that added together give a triangular number (1035 = T₄₅).

The spelling of 636399 in words is "six hundred thirty-six thousand, three hundred ninety-nine".