636945649 has 2 divisors, whose sum is σ = 636945650. Its totient is φ = 636945648.

The previous prime is 636945643. The next prime is 636945671. The reversal of 636945649 is 946549636.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 425679424 + 211266225 = 20632^2 + 14535^2 .

It is a cyclic number.

It is not a de Polignac number, because 636945649 - 2⁷ = 636945521 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 636945596 and 636945605.

It is not a weakly prime, because it can be changed into another prime (636945643) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 318472824 + 318472825.

It is an arithmetic number, because the mean of its divisors is an integer number (318472825).

Almost surely, 2^636945649 is an apocalyptic number.

It is an amenable number.

636945649 is a deficient number, since it is larger than the sum of its proper divisors (1).

636945649 is an equidigital number, since it uses as much as digits as its factorization.

636945649 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4199040, while the sum is 52.

The square root of 636945649 is about 25237.7821727663. The cubic root of 636945649 is about 860.4007727326.

The spelling of 636945649 in words is "six hundred thirty-six million, nine hundred forty-five thousand, six hundred forty-nine".