791939821 has 4 divisors (see below), whose sum is σ = 798948252. Its totient is φ = 784931392.

The previous prime is 791939809. The next prime is 791939867. The reversal of 791939821 is 128939197.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 128939197 = 167 ⋅772091.

It can be written as a sum of positive squares in 2 ways, for example, as 40576900 + 751362921 = 6370^2 + 27411^2 .

It is a cyclic number.

It is not a de Polignac number, because 791939821 - 2⁷ = 791939693 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 (791939891) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3504046 + ... + 3504271.

It is an arithmetic number, because the mean of its divisors is an integer number (199737063).

Almost surely, 2^791939821 is an apocalyptic number.

It is an amenable number.

791939821 is a deficient number, since it is larger than the sum of its proper divisors (7008431).

791939821 is a wasteful number, since it uses less digits than its factorization.

791939821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7008430.

The product of its digits is 244944, while the sum is 49.

The square root of 791939821 is about 28141.4253548039. The cubic root of 791939821 is about 925.1895675758.

The spelling of 791939821 in words is "seven hundred ninety-one million, nine hundred thirty-nine thousand, eight hundred twenty-one".