998779031 has 2 divisors, whose sum is σ = 998779032.
Its totient is φ = 998779030.
The previous prime is 998779013. The next prime is 998779037. The reversal of 998779031 is 130977899.
Together with previous prime (998779013) it forms an Ormiston pair, because they use the same digits, order apart.
It is a strong prime.
It is a cyclic number.
It is not a de Polignac number, because 998779031 - 26 = 998778967 is a prime.
It is a super-2 number, since 2×9987790312 = 1995119105530597922, which contains 22 as substring.
It is a Sophie Germain prime.
It is a Chen prime.
It is equal to p50788889 and since 998779031 and 50788889 have the same sum of digits, it is a Honaker prime.
It is a congruent number.
It is not a weakly prime, because it can be changed into another prime (998779037) by changing a digit.
It is a polite number, since it can be written as a sum of consecutive naturals, namely, 499389515 + 499389516.
It is an arithmetic number, because the mean of its divisors is an integer number (499389516).
Almost surely, 2998779031 is an apocalyptic number.
998779031 is a deficient number, since it is larger than the sum of its proper divisors (1).
998779031 is an equidigital number, since it uses as much as digits as its factorization.
998779031 is an evil number, because the sum of its binary digits is even.
The product of its (nonzero) digits is 857304, while the sum is 53.
The square root of 998779031 is about 31603.4654903541.
The cubic root of 998779031 is about 999.5928445803.
The spelling of 998779031 in words is "nine hundred ninety-eight million, seven hundred seventy-nine thousand, thirty-one".