531511381 has 2 divisors, whose sum is σ = 531511382. Its totient is φ = 531511380.

The previous prime is 531511373. The next prime is 531511417. The reversal of 531511381 is 183115135.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 481583025 + 49928356 = 21945^2 + 7066^2 .

It is a cyclic number.

It is not a de Polignac number, because 531511381 - 2³ = 531511373 is a prime.

It is a super-2 number, since 2×531511381² = 565008696265054322, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (531511081) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 265755690 + 265755691.

It is an arithmetic number, because the mean of its divisors is an integer number (265755691).

Almost surely, 2^531511381 is an apocalyptic number.

It is an amenable number.

531511381 is a deficient number, since it is larger than the sum of its proper divisors (1).

531511381 is an equidigital number, since it uses as much as digits as its factorization.

531511381 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1800, while the sum is 28.

The square root of 531511381 is about 23054.5305959588. The cubic root of 531511381 is about 810.0357556741.

The spelling of 531511381 in words is "five hundred thirty-one million, five hundred eleven thousand, three hundred eighty-one".