989878997 has 2 divisors, whose sum is σ = 989878998. Its totient is φ = 989878996.

The previous prime is 989878979. The next prime is 989879003. The reversal of 989878997 is 799878989.

Together with previous prime (989878979) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 701932036 + 287946961 = 26494^2 + 16969^2 .

It is a cyclic number.

It is not a de Polignac number, because 989878997 - 2²⁶ = 922770133 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (989818997) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 494939498 + 494939499.

It is an arithmetic number, because the mean of its divisors is an integer number (494939499).

Almost surely, 2^989878997 is an apocalyptic number.

It is an amenable number.

989878997 is a deficient number, since it is larger than the sum of its proper divisors (1).

989878997 is an equidigital number, since it uses as much as digits as its factorization.

989878997 is an evil number, because the sum of its binary digits is even.

The product of its digits is 164602368, while the sum is 74.

The square root of 989878997 is about 31462.3425224505. The cubic root of 989878997 is about 996.6148862684.

The spelling of 989878997 in words is "nine hundred eighty-nine million, eight hundred seventy-eight thousand, nine hundred ninety-seven".