1645673757 has 16 divisors (see below), whose sum is σ = 2700593280. Its totient is φ = 868047552.

The previous prime is 1645673741. The next prime is 1645673779. The reversal of 1645673757 is 7573765461.

It is not a de Polignac number, because 1645673757 - 2⁴ = 1645673741 is a prime.

It is a super-2 number, since 2×1645673757² = 5416484228956990098, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1645673707) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3013782 + ... + 3014327.

It is an arithmetic number, because the mean of its divisors is an integer number (168787080).

Almost surely, 2^1645673757 is an apocalyptic number.

It is an amenable number.

1645673757 is a deficient number, since it is larger than the sum of its proper divisors (1054919523).

1645673757 is a wasteful number, since it uses less digits than its factorization.

1645673757 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6028132.

The product of its digits is 3704400, while the sum is 51.

The square root of 1645673757 is about 40566.9047007533. The cubic root of 1645673757 is about 1180.6320842692.

The spelling of 1645673757 in words is "one billion, six hundred forty-five million, six hundred seventy-three thousand, seven hundred fifty-seven".