99666397 has 2 divisors, whose sum is σ = 99666398. Its totient is φ = 99666396.

The previous prime is 99666379. The next prime is 99666403. The reversal of 99666397 is 79366699.

It is a happy number.

Together with previous prime (99666379) 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., 52620516 + 47045881 = 7254^2 + 6859^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-99666397 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (99666377) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 49833198 + 49833199.

It is an arithmetic number, because the mean of its divisors is an integer number (49833199).

Almost surely, 2^99666397 is an apocalyptic number.

It is an amenable number.

99666397 is a deficient number, since it is larger than the sum of its proper divisors (1).

99666397 is an equidigital number, since it uses as much as digits as its factorization.

99666397 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3306744, while the sum is 55.

The square root of 99666397 is about 9983.3059153769. The cubic root of 99666397 is about 463.6421590121.

The spelling of 99666397 in words is "ninety-nine million, six hundred sixty-six thousand, three hundred ninety-seven".