18017813 has 4 divisors (see below), whose sum is σ = 19655808. Its totient is φ = 16379820.

The previous prime is 18017801. The next prime is 18017821. The reversal of 18017813 is 31871081.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 31871081 = 11 ⋅2897371.

It is a cyclic number.

It is not a de Polignac number, because 18017813 - 2⁶ = 18017749 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18017843) 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, 818981 + ... + 819002.

It is an arithmetic number, because the mean of its divisors is an integer number (4913952).

Almost surely, 2^18017813 is an apocalyptic number.

It is an amenable number.

18017813 is a deficient number, since it is larger than the sum of its proper divisors (1637995).

18017813 is a wasteful number, since it uses less digits than its factorization.

18017813 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1637994.

The product of its (nonzero) digits is 1344, while the sum is 29.

The square root of 18017813 is about 4244.7394501901. The cubic root of 18017813 is about 262.1605614125.

Adding to 18017813 its reverse (31871081), we get a palindrome (49888894).

The spelling of 18017813 in words is "eighteen million, seventeen thousand, eight hundred thirteen".