1649982721 has 8 divisors (see below), whose sum is σ = 1705188744. Its totient is φ = 1595489280.

The previous prime is 1649982689. The next prime is 1649982751. The reversal of 1649982721 is 1272899461.

It can be written as a sum of positive squares in 4 ways, for example, as 404496 + 1649578225 = 636^2 + 40615^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1649982721 - 2⁵ = 1649982689 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1649982751) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 173436 + ... + 182701.

It is an arithmetic number, because the mean of its divisors is an integer number (213148593).

Almost surely, 2^1649982721 is an apocalyptic number.

It is an amenable number.

1649982721 is a deficient number, since it is larger than the sum of its proper divisors (55206023).

1649982721 is a wasteful number, since it uses less digits than its factorization.

1649982721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 356291.

The product of its digits is 435456, while the sum is 49.

The square root of 1649982721 is about 40619.9793328357. The cubic root of 1649982721 is about 1181.6616256041.

The spelling of 1649982721 in words is "one billion, six hundred forty-nine million, nine hundred eighty-two thousand, seven hundred twenty-one".