13773491821 has 4 divisors (see below), whose sum is σ = 13777667644. Its totient is φ = 13769316000.

The previous prime is 13773491777. The next prime is 13773491827. The reversal of 13773491821 is 12819437731.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 8989694596 + 4783797225 = 94814^2 + 69165^2 .

It is a cyclic number.

It is not a de Polignac number, because 13773491821 - 2⁹ = 13773491309 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 (13773491827) 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, 2082960 + ... + 2089561.

It is an arithmetic number, because the mean of its divisors is an integer number (3444416911).

Almost surely, 2^13773491821 is an apocalyptic number.

It is an amenable number.

13773491821 is a deficient number, since it is larger than the sum of its proper divisors (4175823).

13773491821 is an equidigital number, since it uses as much as digits as its factorization.

13773491821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4175822.

The product of its digits is 254016, while the sum is 46.

The spelling of 13773491821 in words is "thirteen billion, seven hundred seventy-three million, four hundred ninety-one thousand, eight hundred twenty-one".