771991421 has 12 divisors (see below), whose sum is σ = 795574080. Its totient is φ = 749090160.

The previous prime is 771991393. The next prime is 771991433. The reversal of 771991421 is 124199177.

It is not a de Polignac number, because 771991421 - 2²² = 767797117 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (771991921) 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 11 ways as a sum of consecutive naturals, for example, 846956 + ... + 847866.

It is an arithmetic number, because the mean of its divisors is an integer number (66297840).

Almost surely, 2^771991421 is an apocalyptic number.

It is an amenable number.

771991421 is a deficient number, since it is larger than the sum of its proper divisors (23582659).

771991421 is an equidigital number, since it uses as much as digits as its factorization.

771991421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1604 (or 1567 counting only the distinct ones).

The product of its digits is 31752, while the sum is 41.

The square root of 771991421 is about 27784.7335959876. The cubic root of 771991421 is about 917.3551245634.

The spelling of 771991421 in words is "seven hundred seventy-one million, nine hundred ninety-one thousand, four hundred twenty-one".