18215401 has 4 divisors (see below), whose sum is σ = 18228052. Its totient is φ = 18202752.

The previous prime is 18215387. The next prime is 18215437. The reversal of 18215401 is 10451281.

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 4347225 + 13868176 = 2085^2 + 3724^2 .

It is a cyclic number.

It is not a de Polignac number, because 18215401 - 2¹¹ = 18213353 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18215441) 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, 3840 + ... + 7153.

It is an arithmetic number, because the mean of its divisors is an integer number (4557013).

Almost surely, 2^18215401 is an apocalyptic number.

It is an amenable number.

18215401 is a deficient number, since it is larger than the sum of its proper divisors (12651).

18215401 is a wasteful number, since it uses less digits than its factorization.

18215401 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12650.

The product of its (nonzero) digits is 320, while the sum is 22.

The square root of 18215401 is about 4267.9504448857. The cubic root of 18215401 is about 263.1153864385.

Adding to 18215401 its reverse (10451281), we get a palindrome (28666682).

The spelling of 18215401 in words is "eighteen million, two hundred fifteen thousand, four hundred one".