1981523 has 2 divisors, whose sum is σ = 1981524. Its totient is φ = 1981522.

The previous prime is 1981517. The next prime is 1981543. The reversal of 1981523 is 3251891.

It is a weak prime.

It is an emirp because it is prime and its reverse (3251891) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1981523 - 2⁸ = 1981267 is a prime.

It is a d-powerful number, because it can be written as 1 + 9 + 8³ + 1 + 5⁹ + 2¹³ + 3⁹ .

It is not a weakly prime, because it can be changed into another prime (1981513) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 990761 + 990762.

It is an arithmetic number, because the mean of its divisors is an integer number (990762).

2^1981523 is an apocalyptic number.

1981523 is a deficient number, since it is larger than the sum of its proper divisors (1).

1981523 is an equidigital number, since it uses as much as digits as its factorization.

1981523 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2160, while the sum is 29.

The square root of 1981523 is about 1407.6657984053. The cubic root of 1981523 is about 125.6029113082.

The spelling of 1981523 in words is "one million, nine hundred eighty-one thousand, five hundred twenty-three".