1628978305 has 4 divisors (see below), whose sum is σ = 1954773972. Its totient is φ = 1303182640.

The previous prime is 1628978293. The next prime is 1628978321. The reversal of 1628978305 is 5038798261.

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 1105163536 + 523814769 = 33244^2 + 22887^2 .

It is not a de Polignac number, because 1628978305 - 2⁷ = 1628978177 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 (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 162897826 + ... + 162897835.

It is an arithmetic number, because the mean of its divisors is an integer number (488693493).

Almost surely, 2^1628978305 is an apocalyptic number.

It is an amenable number.

1628978305 is a deficient number, since it is larger than the sum of its proper divisors (325795667).

1628978305 is an equidigital number, since it uses as much as digits as its factorization.

1628978305 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 325795666.

The product of its (nonzero) digits is 725760, while the sum is 49.

The square root of 1628978305 is about 40360.6033775512. The cubic root of 1628978305 is about 1176.6259800855.

The spelling of 1628978305 in words is "one billion, six hundred twenty-eight million, nine hundred seventy-eight thousand, three hundred five".