13618821 has 4 divisors (see below), whose sum is σ = 18158432. Its totient is φ = 9079212.

The previous prime is 13618817. The next prime is 13618837. The reversal of 13618821 is 12881631.

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.

It is not a de Polignac number, because 13618821 - 2² = 13618817 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 (13616821) 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, 2269801 + ... + 2269806.

It is an arithmetic number, because the mean of its divisors is an integer number (4539608).

Almost surely, 2^13618821 is an apocalyptic number.

It is an amenable number.

13618821 is a deficient number, since it is larger than the sum of its proper divisors (4539611).

13618821 is an equidigital number, since it uses as much as digits as its factorization.

13618821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4539610.

The product of its digits is 2304, while the sum is 30.

The square root of 13618821 is about 3690.3686807689. The cubic root of 13618821 is about 238.8066981559.

The spelling of 13618821 in words is "thirteen million, six hundred eighteen thousand, eight hundred twenty-one".