12811821 has 8 divisors (see below), whose sum is σ = 18635424. Its totient is φ = 7764720.

The previous prime is 12811811. The next prime is 12811847.

12811821 is nontrivially palindromic in base 10.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 12811821 - 2⁵ = 12811789 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 12811791 and 12811800.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12811811) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 194086 + ... + 194151.

It is an arithmetic number, because the mean of its divisors is an integer number (2329428).

Almost surely, 2^12811821 is an apocalyptic number.

12811821 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

12811821 is a deficient number, since it is larger than the sum of its proper divisors (5823603).

12811821 is a wasteful number, since it uses less digits than its factorization.

12811821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 388251.

The product of its digits is 256, while the sum is 24.

The square root of 12811821 is about 3579.3604177283. The cubic root of 12811821 is about 233.9934069294.

The spelling of 12811821 in words is "twelve million, eight hundred eleven thousand, eight hundred twenty-one".