1649865673 has 4 divisors (see below), whose sum is σ = 1680995268. Its totient is φ = 1618736080.

The previous prime is 1649865671. The next prime is 1649865697. The reversal of 1649865673 is 3765689461.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 3765689461 = 23531 ⋅160031.

It can be written as a sum of positive squares in 2 ways, for example, as 516062089 + 1133803584 = 22717^2 + 33672^2 .

It is a cyclic number.

It is not a de Polignac number, because 1649865673 - 2¹ = 1649865671 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1649865671) 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 3 ways as a sum of consecutive naturals, for example, 15564718 + ... + 15564823.

It is an arithmetic number, because the mean of its divisors is an integer number (420248817).

Almost surely, 2^1649865673 is an apocalyptic number.

It is an amenable number.

1649865673 is a deficient number, since it is larger than the sum of its proper divisors (31129595).

1649865673 is an equidigital number, since it uses as much as digits as its factorization.

1649865673 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31129594.

The product of its digits is 6531840, while the sum is 55.

The square root of 1649865673 is about 40618.5385384556. The cubic root of 1649865673 is about 1181.6336830083.

The spelling of 1649865673 in words is "one billion, six hundred forty-nine million, eight hundred sixty-five thousand, six hundred seventy-three".