1643736349 has 2 divisors, whose sum is σ = 1643736350. Its totient is φ = 1643736348.

The previous prime is 1643736337. The next prime is 1643736373. The reversal of 1643736349 is 9436373461.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1608571449 + 35164900 = 40107^2 + 5930^2 .

It is a cyclic number.

It is not a de Polignac number, because 1643736349 - 2⁹ = 1643735837 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1643736299 and 1643736308.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1643736389) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 821868174 + 821868175.

It is an arithmetic number, because the mean of its divisors is an integer number (821868175).

Almost surely, 2^1643736349 is an apocalyptic number.

It is an amenable number.

1643736349 is a deficient number, since it is larger than the sum of its proper divisors (1).

1643736349 is an equidigital number, since it uses as much as digits as its factorization.

1643736349 is an evil number, because the sum of its binary digits is even.

The product of its digits is 979776, while the sum is 46.

The square root of 1643736349 is about 40543.0184988735. The cubic root of 1643736349 is about 1180.1685934059.

The spelling of 1643736349 in words is "one billion, six hundred forty-three million, seven hundred thirty-six thousand, three hundred forty-nine".