13699981 has 2 divisors, whose sum is σ = 13699982. Its totient is φ = 13699980.

The previous prime is 13699957. The next prime is 13699991. The reversal of 13699981 is 18999631.

13699981 is digitally balanced in base 3, 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., 12187081 + 1512900 = 3491^2 + 1230^2 .

It is a cyclic number.

It is not a de Polignac number, because 13699981 - 2⁵ = 13699949 is a prime.

It is a super-2 number, since 2×13699981² = 375378958800722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (13699921) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6849990 + 6849991.

It is an arithmetic number, because the mean of its divisors is an integer number (6849991).

Almost surely, 2^13699981 is an apocalyptic number.

It is an amenable number.

13699981 is a deficient number, since it is larger than the sum of its proper divisors (1).

13699981 is an equidigital number, since it uses as much as digits as its factorization.

13699981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 104976, while the sum is 46.

The square root of 13699981 is about 3701.3485380331. The cubic root of 13699981 is about 239.2801404551.

The spelling of 13699981 in words is "thirteen million, six hundred ninety-nine thousand, nine hundred eighty-one".