977128391 has 2 divisors, whose sum is σ = 977128392. Its totient is φ = 977128390.

The previous prime is 977128381. The next prime is 977128421. The reversal of 977128391 is 193821779.

It is a weak prime.

It is an emirp because it is prime and its reverse (193821779) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-977128391 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (977128351) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 488564195 + 488564196.

It is an arithmetic number, because the mean of its divisors is an integer number (488564196).

Almost surely, 2^977128391 is an apocalyptic number.

977128391 is a deficient number, since it is larger than the sum of its proper divisors (1).

977128391 is an equidigital number, since it uses as much as digits as its factorization.

977128391 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 190512, while the sum is 47.

The square root of 977128391 is about 31259.0529447071. The cubic root of 977128391 is about 992.3172569493.

The spelling of 977128391 in words is "nine hundred seventy-seven million, one hundred twenty-eight thousand, three hundred ninety-one".