402018181 has 2 divisors, whose sum is σ = 402018182. Its totient is φ = 402018180.

The previous prime is 402018151. The next prime is 402018187. The reversal of 402018181 is 181810204.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 385493956 + 16524225 = 19634^2 + 4065^2 .

It is a cyclic number.

It is not a de Polignac number, because 402018181 - 2¹¹ = 402016133 is a prime.

It is a super-2 number, since 2×402018181² = 323237235709097522, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (402018187) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 201009090 + 201009091.

It is an arithmetic number, because the mean of its divisors is an integer number (201009091).

Almost surely, 2^402018181 is an apocalyptic number.

It is an amenable number.

402018181 is a deficient number, since it is larger than the sum of its proper divisors (1).

402018181 is an equidigital number, since it uses as much as digits as its factorization.

402018181 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 512, while the sum is 25.

The square root of 402018181 is about 20050.3910435682. The cubic root of 402018181 is about 738.0433952151.

Adding to 402018181 its reverse (181810204), we get a palindrome (583828385).

It can be divided in two parts, 4020 and 18181, that added together give a square (22201 = 149²).

The spelling of 402018181 in words is "four hundred two million, eighteen thousand, one hundred eighty-one".