77128231 has 2 divisors, whose sum is σ = 77128232. Its totient is φ = 77128230.

The previous prime is 77128199. The next prime is 77128237. The reversal of 77128231 is 13282177.

It is a strong prime.

It is an emirp because it is prime and its reverse (13282177) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 77128231 - 2⁵ = 77128199 is a prime.

It is a super-2 number, since 2×77128231² = 11897528034378722, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 77128193 and 77128202.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (77128237) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38564115 + 38564116.

It is an arithmetic number, because the mean of its divisors is an integer number (38564116).

Almost surely, 2^77128231 is an apocalyptic number.

77128231 is a deficient number, since it is larger than the sum of its proper divisors (1).

77128231 is an equidigital number, since it uses as much as digits as its factorization.

77128231 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4704, while the sum is 31.

The square root of 77128231 is about 8782.2679872571. The cubic root of 77128231 is about 425.6681182279.

The spelling of 77128231 in words is "seventy-seven million, one hundred twenty-eight thousand, two hundred thirty-one".