771886991 has 2 divisors, whose sum is σ = 771886992. Its totient is φ = 771886990.

The previous prime is 771886987. The next prime is 771886993. The reversal of 771886991 is 199688177.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 771886991 - 2² = 771886987 is a prime.

Together with 771886993, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (771886993) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 385943495 + 385943496.

It is an arithmetic number, because the mean of its divisors is an integer number (385943496).

Almost surely, 2^771886991 is an apocalyptic number.

771886991 is a deficient number, since it is larger than the sum of its proper divisors (1).

771886991 is an equidigital number, since it uses as much as digits as its factorization.

771886991 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1524096, while the sum is 56.

The square root of 771886991 is about 27782.8542630162. The cubic root of 771886991 is about 917.3137580780.

The spelling of 771886991 in words is "seven hundred seventy-one million, eight hundred eighty-six thousand, nine hundred ninety-one".