18215012897 has 4 divisors (see below), whose sum is σ = 18843116820. Its totient is φ = 17586908976.

The previous prime is 18215012869. The next prime is 18215012923. The reversal of 18215012897 is 79821051281.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 79821051281 = 8893 ⋅8975717.

It can be written as a sum of positive squares in 2 ways, for example, as 15699087616 + 2515925281 = 125296^2 + 50159^2 .

It is a cyclic number.

It is not a de Polignac number, because 18215012897 - 2⁶ = 18215012833 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18215012297) 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, 314051918 + ... + 314051975.

It is an arithmetic number, because the mean of its divisors is an integer number (4710779205).

Almost surely, 2^18215012897 is an apocalyptic number.

It is an amenable number.

18215012897 is a deficient number, since it is larger than the sum of its proper divisors (628103923).

18215012897 is an equidigital number, since it uses as much as digits as its factorization.

18215012897 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 628103922.

The product of its (nonzero) digits is 80640, while the sum is 44.

The spelling of 18215012897 in words is "eighteen billion, two hundred fifteen million, twelve thousand, eight hundred ninety-seven".