1649278705 has 4 divisors (see below), whose sum is σ = 1979134452. Its totient is φ = 1319422960.

The previous prime is 1649278649. The next prime is 1649278727. The reversal of 1649278705 is 5078729461.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5078729461 = 13 ⋅390671497.

It can be written as a sum of positive squares in 2 ways, for example, as 822083584 + 827195121 = 28672^2 + 28761^2 .

It is not a de Polignac number, because 1649278705 - 2⁷ = 1649278577 is a prime.

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 164927866 + ... + 164927875.

It is an arithmetic number, because the mean of its divisors is an integer number (494783613).

Almost surely, 2^1649278705 is an apocalyptic number.

It is an amenable number.

1649278705 is a deficient number, since it is larger than the sum of its proper divisors (329855747).

1649278705 is an equidigital number, since it uses as much as digits as its factorization.

1649278705 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 329855746.

The product of its (nonzero) digits is 846720, while the sum is 49.

The square root of 1649278705 is about 40611.3125249603. The cubic root of 1649278705 is about 1181.4935375734.

The spelling of 1649278705 in words is "one billion, six hundred forty-nine million, two hundred seventy-eight thousand, seven hundred five".