77391231 has 16 divisors (see below), whose sum is σ = 107294208. Its totient is φ = 49579200.

The previous prime is 77391229. The next prime is 77391233. The reversal of 77391231 is 13219377.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (77391229) and next prime (77391233).

It is not a de Polignac number, because 77391231 - 2¹ = 77391229 is a prime.

It is a super-2 number, since 2×77391231² = 11978805271390722, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 77391192 and 77391201.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (77391233) 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 15 ways as a sum of consecutive naturals, for example, 3546 + ... + 12936.

It is an arithmetic number, because the mean of its divisors is an integer number (6705888).

Almost surely, 2^77391231 is an apocalyptic number.

77391231 is a deficient number, since it is larger than the sum of its proper divisors (29902977).

77391231 is a wasteful number, since it uses less digits than its factorization.

77391231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9502.

The product of its digits is 7938, while the sum is 33.

The square root of 77391231 is about 8797.2285976892. The cubic root of 77391231 is about 426.1513987208.

The spelling of 77391231 in words is "seventy-seven million, three hundred ninety-one thousand, two hundred thirty-one".