77909969 has 4 divisors (see below), whose sum is σ = 77927844. Its totient is φ = 77892096.

The previous prime is 77909959. The next prime is 77909983. The reversal of 77909969 is 96990977.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 96990977 = 23 ⋅4216999.

It can be written as a sum of positive squares in 2 ways, for example, as 15499969 + 62410000 = 3937^2 + 7900^2 .

It is a cyclic number.

It is not a de Polignac number, because 77909969 - 2¹² = 77905873 is a prime.

It is a super-2 number, since 2×77909969² = 12139926539161922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (77909939) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2369 + ... + 12705.

It is an arithmetic number, because the mean of its divisors is an integer number (19481961).

Almost surely, 2^77909969 is an apocalyptic number.

It is an amenable number.

77909969 is a deficient number, since it is larger than the sum of its proper divisors (17875).

77909969 is a wasteful number, since it uses less digits than its factorization.

77909969 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17874.

The product of its (nonzero) digits is 1928934, while the sum is 56.

The square root of 77909969 is about 8826.6623930000. The cubic root of 77909969 is about 427.1014152508.

The spelling of 77909969 in words is "seventy-seven million, nine hundred nine thousand, nine hundred sixty-nine".