22018181 has 2 divisors, whose sum is σ = 22018182. Its totient is φ = 22018180.

The previous prime is 22018147. The next prime is 22018201. The reversal of 22018181 is 18181022.

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., 21077281 + 940900 = 4591^2 + 970^2 .

It is a cyclic number.

It is not a de Polignac number, because 22018181 - 2¹⁴ = 22001797 is a prime.

It is a super-2 number, since 2×22018181² = 969600589097522, which contains 22 as substring.

It is a Chen prime.

It is equal to p_1390325 and since 22018181 and 1390325 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 (22018141) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 11009090 + 11009091.

It is an arithmetic number, because the mean of its divisors is an integer number (11009091).

Almost surely, 2^22018181 is an apocalyptic number.

It is an amenable number.

22018181 is a deficient number, since it is larger than the sum of its proper divisors (1).

22018181 is an equidigital number, since it uses as much as digits as its factorization.

22018181 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 256, while the sum is 23.

The square root of 22018181 is about 4692.3534606847. The cubic root of 22018181 is about 280.2810995050.

The spelling of 22018181 in words is "twenty-two million, eighteen thousand, one hundred eighty-one".