1639383985 has 4 divisors (see below), whose sum is σ = 1967260788. Its totient is φ = 1311507184.

The previous prime is 1639383979. The next prime is 1639383989. The reversal of 1639383985 is 5893839361.

It is a happy number.

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 469675584 + 1169708401 = 21672^2 + 34201^2 .

It is a cyclic number.

It is not a de Polignac number, because 1639383985 - 2⁵ = 1639383953 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1639383989) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 163938394 + ... + 163938403.

It is an arithmetic number, because the mean of its divisors is an integer number (491815197).

Almost surely, 2^1639383985 is an apocalyptic number.

It is an amenable number.

1639383985 is a deficient number, since it is larger than the sum of its proper divisors (327876803).

1639383985 is an equidigital number, since it uses as much as digits as its factorization.

1639383985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 327876802.

The product of its digits is 4199040, while the sum is 55.

The square root of 1639383985 is about 40489.3070451940. The cubic root of 1639383985 is about 1179.1260370046.

The spelling of 1639383985 in words is "one billion, six hundred thirty-nine million, three hundred eighty-three thousand, nine hundred eighty-five".