1816864261 has 4 divisors (see below), whose sum is σ = 1822596012. Its totient is φ = 1811132512.

The previous prime is 1816864249. The next prime is 1816864279. The reversal of 1816864261 is 1624686181.

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 80892036 + 1735972225 = 8994^2 + 41665^2 .

It is a cyclic number.

It is not a de Polignac number, because 1816864261 - 2⁹ = 1816863749 is a prime.

It is a super-2 number, since 2×1816864261² = 6601991485798152242, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1816864061) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2865400 + ... + 2866033.

It is an arithmetic number, because the mean of its divisors is an integer number (455649003).

Almost surely, 2^1816864261 is an apocalyptic number.

It is an amenable number.

1816864261 is a deficient number, since it is larger than the sum of its proper divisors (5731751).

1816864261 is an equidigital number, since it uses as much as digits as its factorization.

1816864261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5731750.

The product of its digits is 110592, while the sum is 43.

The square root of 1816864261 is about 42624.6907437462. The cubic root of 1816864261 is about 1220.2275534067.

The spelling of 1816864261 in words is "one billion, eight hundred sixteen million, eight hundred sixty-four thousand, two hundred sixty-one".