998397831 has 4 divisors (see below), whose sum is σ = 1331197112. Its totient is φ = 665598552.

The previous prime is 998397821. The next prime is 998397833. The reversal of 998397831 is 138793899.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 998397831 - 2¹⁰ = 998396807 is a prime.

It is a super-2 number, since 2×998397831² = 1993596457891009122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (998397833) 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, 166399636 + ... + 166399641.

It is an arithmetic number, because the mean of its divisors is an integer number (332799278).

Almost surely, 2^998397831 is an apocalyptic number.

998397831 is a deficient number, since it is larger than the sum of its proper divisors (332799281).

998397831 is a wasteful number, since it uses less digits than its factorization.

998397831 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 332799280.

The product of its digits is 2939328, while the sum is 57.

The square root of 998397831 is about 31597.4339306216. The cubic root of 998397831 is about 999.4656581964.

The spelling of 998397831 in words is "nine hundred ninety-eight million, three hundred ninety-seven thousand, eight hundred thirty-one".