636645945 has 16 divisors (see below), whose sum is σ = 1096990272. Its totient is φ = 313425600.

The previous prime is 636645943. The next prime is 636645949. The reversal of 636645945 is 549546636.

It is a happy number.

It is not a de Polignac number, because 636645945 - 2¹ = 636645943 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 636645894 and 636645903.

It is not an unprimeable number, because it can be changed into a prime (636645943) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1632231 + ... + 1632620.

It is an arithmetic number, because the mean of its divisors is an integer number (68561892).

Almost surely, 2^636645945 is an apocalyptic number.

636645945 is a gapful number since it is divisible by the number (65) formed by its first and last digit.

It is an amenable number.

636645945 is a deficient number, since it is larger than the sum of its proper divisors (460344327).

636645945 is a wasteful number, since it uses less digits than its factorization.

636645945 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3264872.

The product of its digits is 2332800, while the sum is 48.

The square root of 636645945 is about 25231.8438684136. The cubic root of 636645945 is about 860.2658025517.

The spelling of 636645945 in words is "six hundred thirty-six million, six hundred forty-five thousand, nine hundred forty-five".