1531813 has 2 divisors, whose sum is σ = 1531814. Its totient is φ = 1531812.

The previous prime is 1531811. The next prime is 1531843. The reversal of 1531813 is 3181351.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1397124 + 134689 = 1182^2 + 367^2 .

It is an emirp because it is prime and its reverse (3181351) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1531813 - 2¹ = 1531811 is a prime.

Together with 1531811, it forms a pair of twin primes.

1531813 is a lucky number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1531811) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 765906 + 765907.

It is an arithmetic number, because the mean of its divisors is an integer number (765907).

2^1531813 is an apocalyptic number.

It is an amenable number.

1531813 is a deficient number, since it is larger than the sum of its proper divisors (1).

1531813 is an equidigital number, since it uses as much as digits as its factorization.

1531813 is an evil number, because the sum of its binary digits is even.

The product of its digits is 360, while the sum is 22.

The square root of 1531813 is about 1237.6643325232. The cubic root of 1531813 is about 115.2750316964.

The spelling of 1531813 in words is "one million, five hundred thirty-one thousand, eight hundred thirteen".