13758221 has 4 divisors (see below), whose sum is σ = 13766652. Its totient is φ = 13749792.

The previous prime is 13758211. The next prime is 13758229. The reversal of 13758221 is 12285731.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 12460900 + 1297321 = 3530^2 + 1139^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-13758221 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13758229) 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, 896 + ... + 5321.

It is an arithmetic number, because the mean of its divisors is an integer number (3441663).

Almost surely, 2^13758221 is an apocalyptic number.

It is an amenable number.

13758221 is a deficient number, since it is larger than the sum of its proper divisors (8431).

13758221 is an equidigital number, since it uses as much as digits as its factorization.

13758221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8430.

The product of its digits is 3360, while the sum is 29.

The square root of 13758221 is about 3709.2075973178. The cubic root of 13758221 is about 239.6187291136.

The spelling of 13758221 in words is "thirteen million, seven hundred fifty-eight thousand, two hundred twenty-one".