636431 has 4 divisors (see below), whose sum is σ = 638112. Its totient is φ = 634752.

The previous prime is 636421. The next prime is 636469. The reversal of 636431 is 134636.

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 636431 - 2¹⁸ = 374287 is a prime.

It is a super-2 number, since 2×636431² = 810088835522, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 636397 and 636406.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (636421) 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, 26 + ... + 1128.

It is an arithmetic number, because the mean of its divisors is an integer number (159528).

2⁶³⁶⁴³¹ is an apocalyptic number.

636431 is a deficient number, since it is larger than the sum of its proper divisors (1681).

636431 is a wasteful number, since it uses less digits than its factorization.

636431 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1680.

The product of its digits is 1296, while the sum is 23.

The square root of 636431 is about 797.7662564937. The cubic root of 636431 is about 86.0168977072.

The spelling of 636431 in words is "six hundred thirty-six thousand, four hundred thirty-one".