531121891 has 2 divisors, whose sum is σ = 531121892. Its totient is φ = 531121890.

The previous prime is 531121889. The next prime is 531121901. The reversal of 531121891 is 198121135.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 531121891 - 2¹ = 531121889 is a prime.

Together with 531121889, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (531121841) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 265560945 + 265560946.

It is an arithmetic number, because the mean of its divisors is an integer number (265560946).

Almost surely, 2^531121891 is an apocalyptic number.

531121891 is a deficient number, since it is larger than the sum of its proper divisors (1).

531121891 is an equidigital number, since it uses as much as digits as its factorization.

531121891 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2160, while the sum is 31.

The square root of 531121891 is about 23046.0819012690. The cubic root of 531121891 is about 809.8378433714.

The spelling of 531121891 in words is "five hundred thirty-one million, one hundred twenty-one thousand, eight hundred ninety-one".