636621077 has 2 divisors, whose sum is σ = 636621078. Its totient is φ = 636621076.

The previous prime is 636621023. The next prime is 636621091. The reversal of 636621077 is 770126636.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 523219876 + 113401201 = 22874^2 + 10649^2 .

It is a cyclic number.

It is not a de Polignac number, because 636621077 - 2¹⁰ = 636620053 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 636621077.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (636621877) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 318310538 + 318310539.

It is an arithmetic number, because the mean of its divisors is an integer number (318310539).

Almost surely, 2^636621077 is an apocalyptic number.

It is an amenable number.

636621077 is a deficient number, since it is larger than the sum of its proper divisors (1).

636621077 is an equidigital number, since it uses as much as digits as its factorization.

636621077 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 63504, while the sum is 38.

The square root of 636621077 is about 25231.3510736147. The cubic root of 636621077 is about 860.2546014706.

The spelling of 636621077 in words is "six hundred thirty-six million, six hundred twenty-one thousand, seventy-seven".