11855381 has 2 divisors, whose sum is σ = 11855382. Its totient is φ = 11855380.

The previous prime is 11855359. The next prime is 11855383. The reversal of 11855381 is 18355811.

It is a happy number.

11855381 is digitally balanced in base 2, 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., 9424900 + 2430481 = 3070^2 + 1559^2 .

It is a cyclic number.

It is not a de Polignac number, because 11855381 - 2²² = 7661077 is a prime.

It is a super-2 number, since 2×11855381² = 281100117310322, which contains 22 as substring.

It is a Sophie Germain prime.

Together with 11855383, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is equal to p₇₇₉₁₃₅ and since 11855381 and 779135 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (11855383) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5927690 + 5927691.

It is an arithmetic number, because the mean of its divisors is an integer number (5927691).

Almost surely, 2^11855381 is an apocalyptic number.

It is an amenable number.

11855381 is a deficient number, since it is larger than the sum of its proper divisors (1).

11855381 is an equidigital number, since it uses as much as digits as its factorization.

11855381 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4800, while the sum is 32.

The square root of 11855381 is about 3443.1643875946. The cubic root of 11855381 is about 228.0194209885.

The spelling of 11855381 in words is "eleven million, eight hundred fifty-five thousand, three hundred eighty-one".