13756221 has 6 divisors (see below), whose sum is σ = 19870110. Its totient is φ = 9170808.

The previous prime is 13756217. The next prime is 13756243. The reversal of 13756221 is 12265731.

It is a happy number.

13756221 is a `hidden beast` number, since 1 + 37 + 5 + 622 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 9180900 + 4575321 = 3030^2 + 2139^2 .

It is not a de Polignac number, because 13756221 - 2² = 13756217 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13756271) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 764226 + ... + 764243.

It is an arithmetic number, because the mean of its divisors is an integer number (3311685).

Almost surely, 2^13756221 is an apocalyptic number.

It is an amenable number.

13756221 is a deficient number, since it is larger than the sum of its proper divisors (6113889).

13756221 is a wasteful number, since it uses less digits than its factorization.

13756221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1528475 (or 1528472 counting only the distinct ones).

The product of its digits is 2520, while the sum is 27.

The square root of 13756221 is about 3708.9379881578. The cubic root of 13756221 is about 239.6071176152.

The spelling of 13756221 in words is "thirteen million, seven hundred fifty-six thousand, two hundred twenty-one".