1815722449 has 4 divisors (see below), whose sum is σ = 1817360820. Its totient is φ = 1814084080.

The previous prime is 1815722431. The next prime is 1815722453. The reversal of 1815722449 is 9442275181.

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 134722449 + 1681000000 = 11607^2 + 41000^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1815722449 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1815722459) 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 3 ways as a sum of consecutive naturals, for example, 817522 + ... + 819739.

It is an arithmetic number, because the mean of its divisors is an integer number (454340205).

Almost surely, 2^1815722449 is an apocalyptic number.

It is an amenable number.

1815722449 is a deficient number, since it is larger than the sum of its proper divisors (1638371).

1815722449 is a wasteful number, since it uses less digits than its factorization.

1815722449 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1638370.

The product of its digits is 161280, while the sum is 43.

The square root of 1815722449 is about 42611.2948524215. The cubic root of 1815722449 is about 1219.9718816864.

The spelling of 1815722449 in words is "one billion, eight hundred fifteen million, seven hundred twenty-two thousand, four hundred forty-nine".