636166730621 has 2 divisors, whose sum is σ = 636166730622. Its totient is φ = 636166730620.

The previous prime is 636166730603. The next prime is 636166730659. The reversal of 636166730621 is 126037661636.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 614021124025 + 22145606596 = 783595^2 + 148814^2 .

It is a cyclic number.

It is not a de Polignac number, because 636166730621 - 2¹⁴ = 636166714237 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (636166790621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 318083365310 + 318083365311.

It is an arithmetic number, because the mean of its divisors is an integer number (318083365311).

Almost surely, 2^636166730621 is an apocalyptic number.

It is an amenable number.

636166730621 is a deficient number, since it is larger than the sum of its proper divisors (1).

636166730621 is an equidigital number, since it uses as much as digits as its factorization.

636166730621 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 979776, while the sum is 47.

The spelling of 636166730621 in words is "six hundred thirty-six billion, one hundred sixty-six million, seven hundred thirty thousand, six hundred twenty-one".