1669399 has 2 divisors, whose sum is σ = 1669400. Its totient is φ = 1669398.

The previous prime is 1669391. The next prime is 1669427. The reversal of 1669399 is 9939661.

It is a weak prime.

It is an emirp because it is prime and its reverse (9939661) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1669399 - 2³ = 1669391 is a prime.

1669399 is a lucky number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1669391) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 834699 + 834700.

It is an arithmetic number, because the mean of its divisors is an integer number (834700).

2^1669399 is an apocalyptic number.

1669399 is a deficient number, since it is larger than the sum of its proper divisors (1).

1669399 is an equidigital number, since it uses as much as digits as its factorization.

1669399 is an evil number, because the sum of its binary digits is even.

The product of its digits is 78732, while the sum is 43.

The square root of 1669399 is about 1292.0522435258. The cubic root of 1669399 is about 118.6278655635.

The spelling of 1669399 in words is "one million, six hundred sixty-nine thousand, three hundred ninety-nine".