1999867 has 2 divisors, whose sum is σ = 1999868. Its totient is φ = 1999866.

The previous prime is 1999859. The next prime is 1999871. The reversal of 1999867 is 7689991.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1999867 - 2³ = 1999859 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1999867.

It is not a weakly prime, because it can be changed into another prime (1999817) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 999933 + 999934.

It is an arithmetic number, because the mean of its divisors is an integer number (999934).

2^1999867 is an apocalyptic number.

1999867 is a deficient number, since it is larger than the sum of its proper divisors (1).

1999867 is an equidigital number, since it uses as much as digits as its factorization.

1999867 is an evil number, because the sum of its binary digits is even.

The product of its digits is 244944, while the sum is 49.

The square root of 1999867 is about 1414.1665389904. The cubic root of 1999867 is about 125.9893121026.

The spelling of 1999867 in words is "one million, nine hundred ninety-nine thousand, eight hundred sixty-seven".