11812981 has 2 divisors, whose sum is σ = 11812982. Its totient is φ = 11812980.

The previous prime is 11812963. The next prime is 11812987. The reversal of 11812981 is 18921811.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11329956 + 483025 = 3366^2 + 695^2 .

It is a cyclic number.

It is not a de Polignac number, because 11812981 - 2¹³ = 11804789 is a prime.

It is a super-2 number, since 2×11812981² = 279093040212722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (11812987) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5906490 + 5906491.

It is an arithmetic number, because the mean of its divisors is an integer number (5906491).

Almost surely, 2^11812981 is an apocalyptic number.

It is an amenable number.

11812981 is a deficient number, since it is larger than the sum of its proper divisors (1).

11812981 is an equidigital number, since it uses as much as digits as its factorization.

11812981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1152, while the sum is 31.

The square root of 11812981 is about 3437.0017457080. The cubic root of 11812981 is about 227.7472640642.

The spelling of 11812981 in words is "eleven million, eight hundred twelve thousand, nine hundred eighty-one".