636421 has 2 divisors, whose sum is σ = 636422. Its totient is φ = 636420.

The previous prime is 636409. The next prime is 636469. The reversal of 636421 is 124636.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 624100 + 12321 = 790^2 + 111^2 .

It is a cyclic number.

It is not a de Polignac number, because 636421 - 2⁹ = 635909 is a prime.

It is a Chen prime.

It is a nialpdrome in base 15.

It is a junction number, because it is equal to n+sod(n) for n = 636392 and 636401.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (636721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 318210 + 318211.

It is an arithmetic number, because the mean of its divisors is an integer number (318211).

2⁶³⁶⁴²¹ is an apocalyptic number.

It is an amenable number.

636421 is a deficient number, since it is larger than the sum of its proper divisors (1).

636421 is an equidigital number, since it uses as much as digits as its factorization.

636421 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 864, while the sum is 22.

The square root of 636421 is about 797.7599889691. The cubic root of 636421 is about 86.0164471878.

The spelling of 636421 in words is "six hundred thirty-six thousand, four hundred twenty-one".