13749781 has 2 divisors, whose sum is σ = 13749782. Its totient is φ = 13749780.

The previous prime is 13749761. The next prime is 13749793. The reversal of 13749781 is 18794731.

13749781 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., 7474756 + 6275025 = 2734^2 + 2505^2 .

It is a cyclic number.

It is not a de Polignac number, because 13749781 - 2¹¹ = 13747733 is a prime.

It is a super-2 number, since 2×13749781² = 378112955095922, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (13749761) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6874890 + 6874891.

It is an arithmetic number, because the mean of its divisors is an integer number (6874891).

Almost surely, 2^13749781 is an apocalyptic number.

It is an amenable number.

13749781 is a deficient number, since it is larger than the sum of its proper divisors (1).

13749781 is an equidigital number, since it uses as much as digits as its factorization.

13749781 is an evil number, because the sum of its binary digits is even.

The product of its digits is 42336, while the sum is 40.

The square root of 13749781 is about 3708.0697134763. The cubic root of 13749781 is about 239.5697209422.

The spelling of 13749781 in words is "thirteen million, seven hundred forty-nine thousand, seven hundred eighty-one".