77809231 has 4 divisors (see below), whose sum is σ = 79618792. Its totient is φ = 75999672.

The previous prime is 77809211. The next prime is 77809279. The reversal of 77809231 is 13290877.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 13290877 = 1069 ⋅12433.

It is a cyclic number.

It is not a de Polignac number, because 77809231 - 2¹⁹ = 77284943 is a prime.

It is a super-2 number, since 2×77809231² = 12108552857622722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (77809211) 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 3 ways as a sum of consecutive naturals, for example, 904716 + ... + 904801.

It is an arithmetic number, because the mean of its divisors is an integer number (19904698).

Almost surely, 2^77809231 is an apocalyptic number.

77809231 is a deficient number, since it is larger than the sum of its proper divisors (1809561).

77809231 is a wasteful number, since it uses less digits than its factorization.

77809231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1809560.

The product of its (nonzero) digits is 21168, while the sum is 37.

The square root of 77809231 is about 8820.9540867187. The cubic root of 77809231 is about 426.9172543950.

The spelling of 77809231 in words is "seventy-seven million, eight hundred nine thousand, two hundred thirty-one".