18401221213 has 8 divisors (see below), whose sum is σ = 19438643520. Its totient is φ = 17370692640.

The previous prime is 18401221207. The next prime is 18401221219. The reversal of 18401221213 is 31212210481.

It is an interprime number because it is at equal distance from previous prime (18401221207) and next prime (18401221219).

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 18401221213 - 2³³ = 9811286621 is a prime.

It is a super-3 number, since 3×18401221213³ (a number of 32 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18401221219) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1717945 + ... + 1728622.

It is an arithmetic number, because the mean of its divisors is an integer number (2429830440).

Almost surely, 2^18401221213 is an apocalyptic number.

It is an amenable number.

18401221213 is a deficient number, since it is larger than the sum of its proper divisors (1037422307).

18401221213 is a wasteful number, since it uses less digits than its factorization.

18401221213 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3446867.

The product of its (nonzero) digits is 768, while the sum is 25.

Adding to 18401221213 its reverse (31212210481), we get a palindrome (49613431694).

The spelling of 18401221213 in words is "eighteen billion, four hundred one million, two hundred twenty-one thousand, two hundred thirteen".