77991849 has 16 divisors (see below), whose sum is σ = 124432000. Its totient is φ = 47994768.

The previous prime is 77991821. The next prime is 77991871. The reversal of 77991849 is 94819977.

It is not a de Polignac number, because 77991849 - 2⁸ = 77991593 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 77991795 and 77991804.

It is not an unprimeable number, because it can be changed into a prime (77991049) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 110749 + ... + 111450.

It is an arithmetic number, because the mean of its divisors is an integer number (7777000).

Almost surely, 2^77991849 is an apocalyptic number.

It is an amenable number.

77991849 is a deficient number, since it is larger than the sum of its proper divisors (46440151).

77991849 is a wasteful number, since it uses less digits than its factorization.

77991849 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 222221 (or 222215 counting only the distinct ones).

The product of its digits is 1143072, while the sum is 54.

The square root of 77991849 is about 8831.2993947663. The cubic root of 77991849 is about 427.2509845569.

The spelling of 77991849 in words is "seventy-seven million, nine hundred ninety-one thousand, eight hundred forty-nine".