999977777 has 4 divisors (see below), whose sum is σ = 1000107636. Its totient is φ = 999847920.

The previous prime is 999977773. The next prime is 999977833. The reversal of 999977777 is 777779999.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 777779999 = 5483 ⋅141853.

It can be written as a sum of positive squares in 2 ways, for example, as 409293361 + 590684416 = 20231^2 + 24304^2 .

It is a cyclic number.

It is not a de Polignac number, because 999977777 - 2² = 999977773 is a prime.

It is a super-4 number, since 4×999977777⁴ (a number of 37 digits) contains 4444 as substring.

It is a Duffinian number.

It is a nialpdrome in base 10.

It is a zygodrome in base 10.

It is a self number, because there is not a number n which added to its sum of digits gives 999977777.

It is not an unprimeable number, because it can be changed into a prime (999977773) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 52598 + ... + 69039.

It is an arithmetic number, because the mean of its divisors is an integer number (250026909).

Almost surely, 2^999977777 is an apocalyptic number.

It is an amenable number.

999977777 is a deficient number, since it is larger than the sum of its proper divisors (129859).

999977777 is a wasteful number, since it uses less digits than its factorization.

999977777 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 129858.

The product of its digits is 110270727, while the sum is 71.

The square root of 999977777 is about 31622.4252232494. The cubic root of 999977777 is about 999.9925922785.

The spelling of 999977777 in words is "nine hundred ninety-nine million, nine hundred seventy-seven thousand, seven hundred seventy-seven".