99778309 has 2 divisors, whose sum is σ = 99778310. Its totient is φ = 99778308.

The previous prime is 99778271. The next prime is 99778339. The reversal of 99778309 is 90387799.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 89397025 + 10381284 = 9455^2 + 3222^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-99778309 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (99778339) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 49889154 + 49889155.

It is an arithmetic number, because the mean of its divisors is an integer number (49889155).

Almost surely, 2^99778309 is an apocalyptic number.

It is an amenable number.

99778309 is a deficient number, since it is larger than the sum of its proper divisors (1).

99778309 is an equidigital number, since it uses as much as digits as its factorization.

99778309 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 52.

The square root of 99778309 is about 9988.9092998185. The cubic root of 99778309 is about 463.8156300923.

The spelling of 99778309 in words is "ninety-nine million, seven hundred seventy-eight thousand, three hundred nine".