811214821 has 4 divisors (see below), whose sum is σ = 814299552. Its totient is φ = 808130092.

The previous prime is 811214779. The next prime is 811214843. The reversal of 811214821 is 128412118.

811214821 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-811214821 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 811214821.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (811214021) 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, 1541971 + ... + 1542496.

It is an arithmetic number, because the mean of its divisors is an integer number (203574888).

Almost surely, 2^811214821 is an apocalyptic number.

It is an amenable number.

811214821 is a deficient number, since it is larger than the sum of its proper divisors (3084731).

811214821 is a wasteful number, since it uses less digits than its factorization.

811214821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3084730.

The product of its digits is 1024, while the sum is 28.

The square root of 811214821 is about 28481.8331748502. The cubic root of 811214821 is about 932.6355352162.

Adding to 811214821 its reverse (128412118), we get a palindrome (939626939).

The spelling of 811214821 in words is "eight hundred eleven million, two hundred fourteen thousand, eight hundred twenty-one".