99977779 has 8 divisors (see below), whose sum is σ = 110147760. Its totient is φ = 89988000.

The previous prime is 99977771. The next prime is 99977797. The reversal of 99977779 is 97777999.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 99977779 - 2³ = 99977771 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 99977779.

It is not an unprimeable number, because it can be changed into a prime (99977771) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 43884 + ... + 46105.

It is an arithmetic number, because the mean of its divisors is an integer number (13768470).

Almost surely, 2^99977779 is an apocalyptic number.

99977779 is a deficient number, since it is larger than the sum of its proper divisors (10169981).

99977779 is a wasteful number, since it uses less digits than its factorization.

99977779 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 90101.

The product of its digits is 15752961, while the sum is 64.

The square root of 99977779 is about 9998.8888882715. Note that the first 6 decimals coincide. The cubic root of 99977779 is about 464.1245005659.

The spelling of 99977779 in words is "ninety-nine million, nine hundred seventy-seven thousand, seven hundred seventy-nine".