997991279 has 8 divisors (see below), whose sum is σ = 1032130560. Its totient is φ = 964389816.

The previous prime is 997991263. The next prime is 997991287. The reversal of 997991279 is 972199799.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 997991279 - 2⁴ = 997991263 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (997991179) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 130679 + ... + 138104.

It is an arithmetic number, because the mean of its divisors is an integer number (129016320).

Almost surely, 2^997991279 is an apocalyptic number.

997991279 is a deficient number, since it is larger than the sum of its proper divisors (34139281).

997991279 is a wasteful number, since it uses less digits than its factorization.

997991279 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 268909.

The product of its digits is 5786802, while the sum is 62.

The square root of 997991279 is about 31590.9999683454. Note that the first 4 decimals coincide. The cubic root of 997991279 is about 999.3299775035.

The spelling of 997991279 in words is "nine hundred ninety-seven million, nine hundred ninety-one thousand, two hundred seventy-nine".