13001981 has 2 divisors, whose sum is σ = 13001982. Its totient is φ = 13001980.

The previous prime is 13001959. The next prime is 13001993. The reversal of 13001981 is 18910031.

13001981 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., 12313081 + 688900 = 3509^2 + 830^2 .

It is a cyclic number.

It is not a de Polignac number, because 13001981 - 2⁶ = 13001917 is a prime.

It is a super-2 number, since 2×13001981² = 338103019848722, 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 (13031981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6500990 + 6500991.

It is an arithmetic number, because the mean of its divisors is an integer number (6500991).

Almost surely, 2^13001981 is an apocalyptic number.

It is an amenable number.

13001981 is a deficient number, since it is larger than the sum of its proper divisors (1).

13001981 is an equidigital number, since it uses as much as digits as its factorization.

13001981 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 216, while the sum is 23.

The square root of 13001981 is about 3605.8259802714. The cubic root of 13001981 is about 235.1454117399.

The spelling of 13001981 in words is "thirteen million, one thousand, nine hundred eighty-one".