1643244157 has 16 divisors (see below), whose sum is σ = 1758504384. Its totient is φ = 1530144000.

The previous prime is 1643244151. The next prime is 1643244193. The reversal of 1643244157 is 7514423461.

It is a cyclic number.

It is not a de Polignac number, because 1643244157 - 2³ = 1643244149 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1643244151) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 647982 + ... + 650512.

It is an arithmetic number, because the mean of its divisors is an integer number (109906524).

Almost surely, 2^1643244157 is an apocalyptic number.

1643244157 is a gapful number since it is divisible by the number (17) formed by its first and last digit.

It is an amenable number.

1643244157 is a deficient number, since it is larger than the sum of its proper divisors (115260227).

1643244157 is a wasteful number, since it uses less digits than its factorization.

1643244157 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2940.

The product of its digits is 80640, while the sum is 37.

The square root of 1643244157 is about 40536.9480474295. The cubic root of 1643244157 is about 1180.0507870988.

The spelling of 1643244157 in words is "one billion, six hundred forty-three million, two hundred forty-four thousand, one hundred fifty-seven".