13913821 has 2 divisors, whose sum is σ = 13913822. Its totient is φ = 13913820.

The previous prime is 13913819. The next prime is 13913839. The reversal of 13913821 is 12831931.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13032100 + 881721 = 3610^2 + 939^2 .

It is a cyclic number.

It is not a de Polignac number, because 13913821 - 2¹ = 13913819 is a prime.

Together with 13913819, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 13913821.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (13913891) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6956910 + 6956911.

It is an arithmetic number, because the mean of its divisors is an integer number (6956911).

Almost surely, 2^13913821 is an apocalyptic number.

It is an amenable number.

13913821 is a deficient number, since it is larger than the sum of its proper divisors (1).

13913821 is an equidigital number, since it uses as much as digits as its factorization.

13913821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1296, while the sum is 28.

The square root of 13913821 is about 3730.1234564019. The cubic root of 13913821 is about 240.5186757108.

The spelling of 13913821 in words is "thirteen million, nine hundred thirteen thousand, eight hundred twenty-one".