918871997 has 2 divisors, whose sum is σ = 918871998. Its totient is φ = 918871996.

The previous prime is 918871991. The next prime is 918871999. The reversal of 918871997 is 799178819.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 880071556 + 38800441 = 29666^2 + 6229^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-918871997 is a prime.

Together with 918871999, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (918871991) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 459435998 + 459435999.

It is an arithmetic number, because the mean of its divisors is an integer number (459435999).

Almost surely, 2^918871997 is an apocalyptic number.

It is an amenable number.

918871997 is a deficient number, since it is larger than the sum of its proper divisors (1).

918871997 is an equidigital number, since it uses as much as digits as its factorization.

918871997 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2286144, while the sum is 59.

The square root of 918871997 is about 30312.9014942483. The cubic root of 918871997 is about 972.1911697719.

The spelling of 918871997 in words is "nine hundred eighteen million, eight hundred seventy-one thousand, nine hundred ninety-seven".