1999969 has 2 divisors, whose sum is σ = 1999970.
Its totient is φ = 1999968.
The previous prime is 1999957. The next prime is 1999979. The reversal of 1999969 is 9699991.
It is a strong prime.
It can be written as a sum of positive squares in only one way, i.e., 1166400 + 833569 = 1080^2 + 913^2
It is a cyclic number.
It is not a de Polignac number, because 1999969 - 211 = 1997921 is a prime.
It is a super-2 number, since 2×19999692 = 7999752001922, which contains 22 as substring.
1999969 is a lucky number.
It is not a weakly prime, because it can be changed into another prime (1999979) by changing a digit.
It is a polite number, since it can be written as a sum of consecutive naturals, namely, 999984 + 999985.
It is an arithmetic number, because the mean of its divisors is an integer number (999985).
21999969 is an apocalyptic number.
It is an amenable number.
1999969 is a deficient number, since it is larger than the sum of its proper divisors (1).
1999969 is an equidigital number, since it uses as much as digits as its factorization.
1999969 is an odious number, because the sum of its binary digits is odd.
The product of its digits is 354294, while the sum is 52.
The square root of 1999969 is about 1414.2026021755.
The cubic root of 1999969 is about 125.9914540269.
The spelling of 1999969 in words is "one million, nine hundred ninety-nine thousand, nine hundred sixty-nine".