1643349757 has 16 divisors (see below), whose sum is σ = 1955952000. Its totient is φ = 1350861120.

The previous prime is 1643349739. The next prime is 1643349781. The reversal of 1643349757 is 7579433461.

It is a happy number.

It is not a de Polignac number, because 1643349757 - 2⁷ = 1643349629 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1643349757.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1643349707) 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, 3082 + ... + 57412.

It is an arithmetic number, because the mean of its divisors is an integer number (122247000).

Almost surely, 2^1643349757 is an apocalyptic number.

It is an amenable number.

1643349757 is a deficient number, since it is larger than the sum of its proper divisors (312602243).

1643349757 is a wasteful number, since it uses less digits than its factorization.

1643349757 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 54516.

The product of its digits is 1905120, while the sum is 49.

The square root of 1643349757 is about 40538.2505419264. The cubic root of 1643349757 is about 1180.0760644733.

The spelling of 1643349757 in words is "one billion, six hundred forty-three million, three hundred forty-nine thousand, seven hundred fifty-seven".