3945537649 has 4 divisors (see below), whose sum is σ = 3947316340. Its totient is φ = 3943758960.

The previous prime is 3945537643. The next prime is 3945537709. The reversal of 3945537649 is 9467355493.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 3437711424 + 507826225 = 58632^2 + 22535^2 .

It is a cyclic number.

It is not a de Polignac number, because 3945537649 - 2¹⁹ = 3945013361 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 3945537649.

It is not an unprimeable number, because it can be changed into a prime (3945537643) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 886014 + ... + 890455.

It is an arithmetic number, because the mean of its divisors is an integer number (986829085).

Almost surely, 2^3945537649 is an apocalyptic number.

It is an amenable number.

3945537649 is a deficient number, since it is larger than the sum of its proper divisors (1778691).

3945537649 is a wasteful number, since it uses less digits than its factorization.

3945537649 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1778690.

The product of its digits is 12247200, while the sum is 55.

The square root of 3945537649 is about 62813.5148594632. The cubic root of 3945537649 is about 1580.1636385822.

The spelling of 3945537649 in words is "three billion, nine hundred forty-five million, five hundred thirty-seven thousand, six hundred forty-nine".