999978773 has 2 divisors, whose sum is σ = 999978774. Its totient is φ = 999978772.

The previous prime is 999978767. The next prime is 999978779. The reversal of 999978773 is 377879999.

It is a balanced prime because it is at equal distance from previous prime (999978767) and next prime (999978779).

It can be written as a sum of positive squares in only one way, i.e., 999950884 + 27889 = 31622^2 + 167^2 .

It is a cyclic number.

It is not a de Polignac number, because 999978773 - 2⁸ = 999978517 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (999978779) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 499989386 + 499989387.

It is an arithmetic number, because the mean of its divisors is an integer number (499989387).

Almost surely, 2^999978773 is an apocalyptic number.

It is an amenable number.

999978773 is a deficient number, since it is larger than the sum of its proper divisors (1).

999978773 is an equidigital number, since it uses as much as digits as its factorization.

999978773 is an evil number, because the sum of its binary digits is even.

The product of its digits is 54010152, while the sum is 68.

The square root of 999978773 is about 31622.4409715632. The cubic root of 999978773 is about 999.9929242833.

The spelling of 999978773 in words is "nine hundred ninety-nine million, nine hundred seventy-eight thousand, seven hundred seventy-three".