1988669 has 2 divisors, whose sum is σ = 1988670. Its totient is φ = 1988668.

The previous prime is 1988659. The next prime is 1988671. The reversal of 1988669 is 9668891.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1612900 + 375769 = 1270^2 + 613^2 .

It is a cyclic number.

It is not a de Polignac number, because 1988669 - 2⁴ = 1988653 is a prime.

It is a super-2 number, since 2×1988669² = 7909608783122, which contains 22 as substring.

It is a Sophie Germain prime.

Together with 1988671, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1988659) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 994334 + 994335.

It is an arithmetic number, because the mean of its divisors is an integer number (994335).

2^1988669 is an apocalyptic number.

It is an amenable number.

1988669 is a deficient number, since it is larger than the sum of its proper divisors (1).

1988669 is an equidigital number, since it uses as much as digits as its factorization.

1988669 is an evil number, because the sum of its binary digits is even.

The product of its digits is 186624, while the sum is 47.

The square root of 1988669 is about 1410.2017586147. The cubic root of 1988669 is about 125.7537181372.

It can be divided in two parts, 19 and 88669, that added together give a palindrome (88688).

The spelling of 1988669 in words is "one million, nine hundred eighty-eight thousand, six hundred sixty-nine".