13641781 has 2 divisors, whose sum is σ = 13641782. Its totient is φ = 13641780.

The previous prime is 13641763. The next prime is 13641811. The reversal of 13641781 is 18714631.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12180100 + 1461681 = 3490^2 + 1209^2 .

It is a cyclic number.

It is not a de Polignac number, because 13641781 - 2⁹ = 13641269 is a prime.

It is a super-2 number, since 2×13641781² = 372196377703922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (13641721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6820890 + 6820891.

It is an arithmetic number, because the mean of its divisors is an integer number (6820891).

Almost surely, 2^13641781 is an apocalyptic number.

It is an amenable number.

13641781 is a deficient number, since it is larger than the sum of its proper divisors (1).

13641781 is an equidigital number, since it uses as much as digits as its factorization.

13641781 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4032, while the sum is 31.

The square root of 13641781 is about 3693.4781710469. The cubic root of 13641781 is about 238.9408243871.

The spelling of 13641781 in words is "thirteen million, six hundred forty-one thousand, seven hundred eighty-one".