1997899 has 2 divisors, whose sum is σ = 1997900. Its totient is φ = 1997898.

The previous prime is 1997887. The next prime is 1997903. The reversal of 1997899 is 9987991.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1997899 - 2⁵ = 1997867 is a prime.

It is not a weakly prime, because it can be changed into another prime (1997599) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 998949 + 998950.

It is an arithmetic number, because the mean of its divisors is an integer number (998950).

2^1997899 is an apocalyptic number.

1997899 is a deficient number, since it is larger than the sum of its proper divisors (1).

1997899 is an equidigital number, since it uses as much as digits as its factorization.

1997899 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 367416, while the sum is 52.

The square root of 1997899 is about 1413.4705515150. The cubic root of 1997899 is about 125.9479712963.

The spelling of 1997899 in words is "one million, nine hundred ninety-seven thousand, eight hundred ninety-nine".