99778949 has 2 divisors, whose sum is σ = 99778950. Its totient is φ = 99778948.

The previous prime is 99778909. The next prime is 99778969. The reversal of 99778949 is 94987799.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 90820900 + 8958049 = 9530^2 + 2993^2 .

It is a cyclic number.

It is not a de Polignac number, because 99778949 - 2¹⁶ = 99713413 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 99778891 and 99778900.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (99778909) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 49889474 + 49889475.

It is an arithmetic number, because the mean of its divisors is an integer number (49889475).

Almost surely, 2^99778949 is an apocalyptic number.

It is an amenable number.

99778949 is a deficient number, since it is larger than the sum of its proper divisors (1).

99778949 is an equidigital number, since it uses as much as digits as its factorization.

99778949 is an evil number, because the sum of its binary digits is even.

The product of its digits is 10287648, while the sum is 62.

The square root of 99778949 is about 9988.9413352967. The cubic root of 99778949 is about 463.8166217619.

The spelling of 99778949 in words is "ninety-nine million, seven hundred seventy-eight thousand, nine hundred forty-nine".