18215641 has 2 divisors, whose sum is σ = 18215642. Its totient is φ = 18215640.

The previous prime is 18215629. The next prime is 18215651. The reversal of 18215641 is 14651281.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14899600 + 3316041 = 3860^2 + 1821^2 .

It is a cyclic number.

It is not a de Polignac number, because 18215641 - 2⁷ = 18215513 is a prime.

It is not a weakly prime, because it can be changed into another prime (18215651) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9107820 + 9107821.

It is an arithmetic number, because the mean of its divisors is an integer number (9107821).

Almost surely, 2^18215641 is an apocalyptic number.

It is an amenable number.

18215641 is a deficient number, since it is larger than the sum of its proper divisors (1).

18215641 is an equidigital number, since it uses as much as digits as its factorization.

18215641 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1920, while the sum is 28.

The square root of 18215641 is about 4267.9785613332. The cubic root of 18215641 is about 263.1165420067.

The spelling of 18215641 in words is "eighteen million, two hundred fifteen thousand, six hundred forty-one".