997939 has 4 divisors (see below), whose sum is σ = 1002456. Its totient is φ = 993424.

The previous prime is 997933. The next prime is 997949. The reversal of 997939 is 939799.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 939799 = 7 ⋅134257.

It is a cyclic number.

It is not a de Polignac number, because 997939 - 2⁷ = 997811 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (997933) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1909 + ... + 2374.

It is an arithmetic number, because the mean of its divisors is an integer number (250614).

2⁹⁹⁷⁹³⁹ is an apocalyptic number.

997939 is a deficient number, since it is larger than the sum of its proper divisors (4517).

997939 is a wasteful number, since it uses less digits than its factorization.

997939 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4516.

The product of its digits is 137781, while the sum is 46.

The square root of 997939 is about 998.9689684870. The cubic root of 997939 is about 99.9312527490.

It can be divided in two parts, 997 and 939, that added together give a square (1936 = 44²).

The spelling of 997939 in words is "nine hundred ninety-seven thousand, nine hundred thirty-nine".