1813822921 has 3 divisors (see below), whose sum is σ = 1813865511. Its totient is φ = 1813780332.

The previous prime is 1813822909. The next prime is 1813822949. The reversal of 1813822921 is 1292283181.

The square root of 1813822921 is 42589.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in only one way, i.e., 231374521 + 1582448400 = 15211^2 + 39780^2 .

It is not a de Polignac number, because 1813822921 - 2⁵ = 1813822889 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1813822321) 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 2 ways as a sum of consecutive naturals, for example, 21295 + ... + 63883.

It is an arithmetic number, because the mean of its divisors is an integer number (604621837).

Almost surely, 2^1813822921 is an apocalyptic number.

1813822921 is the 42589-th square number.

1813822921 is the 21295-th centered octagonal number.

It is an amenable number.

1813822921 is a deficient number, since it is larger than the sum of its proper divisors (42590).

1813822921 is an frugal number, since it uses more digits than its factorization.

1813822921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 85178 (or 42589 counting only the distinct ones).

The product of its digits is 13824, while the sum is 37.

The cubic root of 1813822921 is about 1219.5463064873.

The spelling of 1813822921 in words is "one billion, eight hundred thirteen million, eight hundred twenty-two thousand, nine hundred twenty-one".