1985443217 has 2 divisors, whose sum is σ = 1985443218. Its totient is φ = 1985443216.

The previous prime is 1985443181. The next prime is 1985443261. The reversal of 1985443217 is 7123445891.

It is an a-pointer prime, because the next prime (1985443261) can be obtained adding 1985443217 to its sum of digits (44).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1805910016 + 179533201 = 42496^2 + 13399^2 .

It is a cyclic number.

It is not a de Polignac number, because 1985443217 - 2¹² = 1985439121 is a prime.

It is not a weakly prime, because it can be changed into another prime (1985443297) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 992721608 + 992721609.

It is an arithmetic number, because the mean of its divisors is an integer number (992721609).

Almost surely, 2^1985443217 is an apocalyptic number.

It is an amenable number.

1985443217 is a deficient number, since it is larger than the sum of its proper divisors (1).

1985443217 is an equidigital number, since it uses as much as digits as its factorization.

1985443217 is an evil number, because the sum of its binary digits is even.

The product of its digits is 241920, while the sum is 44.

The square root of 1985443217 is about 44558.3125465945. The cubic root of 1985443217 is about 1256.8568708419.

The spelling of 1985443217 in words is "one billion, nine hundred eighty-five million, four hundred forty-three thousand, two hundred seventeen".