997809139 has 2 divisors, whose sum is σ = 997809140. Its totient is φ = 997809138.

The previous prime is 997809103. The next prime is 997809157. The reversal of 997809139 is 931908799.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 997809139 - 2⁷ = 997809011 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 997809139.

It is not a weakly prime, because it can be changed into another prime (997809179) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 498904569 + 498904570.

It is an arithmetic number, because the mean of its divisors is an integer number (498904570).

Almost surely, 2^997809139 is an apocalyptic number.

997809139 is a deficient number, since it is larger than the sum of its proper divisors (1).

997809139 is an equidigital number, since it uses as much as digits as its factorization.

997809139 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1102248, while the sum is 55.

The square root of 997809139 is about 31588.1170537277. The cubic root of 997809139 is about 999.2691790308.

The spelling of 997809139 in words is "nine hundred ninety-seven million, eight hundred nine thousand, one hundred thirty-nine".