1581609823 has 2 divisors, whose sum is σ = 1581609824. Its totient is φ = 1581609822.

The previous prime is 1581609817. The next prime is 1581609851. The reversal of 1581609823 is 3289061851.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1581609823 - 2¹⁷ = 1581478751 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1581609823.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1581609023) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 790804911 + 790804912.

It is an arithmetic number, because the mean of its divisors is an integer number (790804912).

Almost surely, 2^1581609823 is an apocalyptic number.

1581609823 is a deficient number, since it is larger than the sum of its proper divisors (1).

1581609823 is an equidigital number, since it uses as much as digits as its factorization.

1581609823 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 103680, while the sum is 43.

The square root of 1581609823 is about 39769.4584197472. The cubic root of 1581609823 is about 1165.1087161158.

The spelling of 1581609823 in words is "one billion, five hundred eighty-one million, six hundred nine thousand, eight hundred twenty-three".