13903781 has 2 divisors, whose sum is σ = 13903782. Its totient is φ = 13903780.

The previous prime is 13903777. The next prime is 13903783. The reversal of 13903781 is 18730931.

13903781 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12013156 + 1890625 = 3466^2 + 1375^2 .

It is a cyclic number.

It is not a de Polignac number, because 13903781 - 2² = 13903777 is a prime.

It is a super-2 number, since 2×13903781² = 386630252191922, which contains 22 as substring.

Together with 13903783, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (13903783) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6951890 + 6951891.

It is an arithmetic number, because the mean of its divisors is an integer number (6951891).

Almost surely, 2^13903781 is an apocalyptic number.

It is an amenable number.

13903781 is a deficient number, since it is larger than the sum of its proper divisors (1).

13903781 is an equidigital number, since it uses as much as digits as its factorization.

13903781 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4536, while the sum is 32.

The square root of 13903781 is about 3728.7774135767. Note that the first 3 decimals coincide. The cubic root of 13903781 is about 240.4608102602.

The spelling of 13903781 in words is "thirteen million, nine hundred three thousand, seven hundred eighty-one".