1997939 has 2 divisors, whose sum is σ = 1997940. Its totient is φ = 1997938.

The previous prime is 1997921. The next prime is 1997969. The reversal of 1997939 is 9397991.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1997939 - 2⁸ = 1997683 is a prime.

It is a zygodrome in base 2.

It is a junction number, because it is equal to n+sod(n) for n = 1997893 and 1997902.

It is not a weakly prime, because it can be changed into another prime (1997969) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 998969 + 998970.

It is an arithmetic number, because the mean of its divisors is an integer number (998970).

2^1997939 is an apocalyptic number.

1997939 is a deficient number, since it is larger than the sum of its proper divisors (1).

1997939 is an equidigital number, since it uses as much as digits as its factorization.

1997939 is an evil number, because the sum of its binary digits is even.

The product of its digits is 137781, while the sum is 47.

The square root of 1997939 is about 1413.4847010138. The cubic root of 1997939 is about 125.9488118268.

The spelling of 1997939 in words is "one million, nine hundred ninety-seven thousand, nine hundred thirty-nine".