11533981 has 2 divisors, whose sum is σ = 11533982. Its totient is φ = 11533980.

The previous prime is 11533961. The next prime is 11533987. The reversal of 11533981 is 18933511.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 10304100 + 1229881 = 3210^2 + 1109^2 .

It is an emirp because it is prime and its reverse (18933511) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 11533981 - 2⁷ = 11533853 is a prime.

It is a super-2 number, since 2×11533981² = 266065435416722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (11533987) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5766990 + 5766991.

It is an arithmetic number, because the mean of its divisors is an integer number (5766991).

Almost surely, 2^11533981 is an apocalyptic number.

It is an amenable number.

11533981 is a deficient number, since it is larger than the sum of its proper divisors (1).

11533981 is an equidigital number, since it uses as much as digits as its factorization.

11533981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3240, while the sum is 31.

The square root of 11533981 is about 3396.1715209924. The cubic root of 11533981 is about 225.9399754446.

The spelling of 11533981 in words is "eleven million, five hundred thirty-three thousand, nine hundred eighty-one".