13784821 has 2 divisors, whose sum is σ = 13784822. Its totient is φ = 13784820.

The previous prime is 13784761. The next prime is 13784839. The reversal of 13784821 is 12848731.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 10595025 + 3189796 = 3255^2 + 1786^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-13784821 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (13784851) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6892410 + 6892411.

It is an arithmetic number, because the mean of its divisors is an integer number (6892411).

Almost surely, 2^13784821 is an apocalyptic number.

It is an amenable number.

13784821 is a deficient number, since it is larger than the sum of its proper divisors (1).

13784821 is an equidigital number, since it uses as much as digits as its factorization.

13784821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 10752, while the sum is 34.

The square root of 13784821 is about 3712.7915373745. The cubic root of 13784821 is about 239.7730551437.

The spelling of 13784821 in words is "thirteen million, seven hundred eighty-four thousand, eight hundred twenty-one".