22381 has 2 divisors, whose sum is σ = 22382. Its totient is φ = 22380.

The previous prime is 22369. The next prime is 22391. The reversal of 22381 is 18322.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19881 + 2500 = 141^2 + 50^2 .

It is a cyclic number.

It is not a de Polignac number, because 22381 - 2⁵ = 22349 is a prime.

It is a super-2 number, since 2×22381² = 1001818322, which contains 22 as substring.

It is an Ulam number.

22381 is a lucky number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (22391) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 11190 + 11191.

It is an arithmetic number, because the mean of its divisors is an integer number (11191).

2²²³⁸¹ is an apocalyptic number.

It is an amenable number.

22381 is a deficient number, since it is larger than the sum of its proper divisors (1).

22381 is an equidigital number, since it uses as much as digits as its factorization.

22381 is an evil number, because the sum of its binary digits is even.

The product of its digits is 96, while the sum is 16.

The square root of 22381 is about 149.6028074603. The cubic root of 22381 is about 28.1812225144.

The spelling of 22381 in words is "twenty-two thousand, three hundred eighty-one".