1809909529381 has 2 divisors, whose sum is σ = 1809909529382. Its totient is φ = 1809909529380.

The previous prime is 1809909529247. The next prime is 1809909529409. The reversal of 1809909529381 is 1839259099081.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1737543149281 + 72366380100 = 1318159^2 + 269010^2 .

It is a cyclic number.

It is not a de Polignac number, because 1809909529381 - 2³⁵ = 1775549791013 is a prime.

It is a super-2 number, since 2×1809909529381² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1809909529081) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 904954764690 + 904954764691.

It is an arithmetic number, because the mean of its divisors is an integer number (904954764691).

Almost surely, 2^{1809909529381} is an apocalyptic number.

It is an amenable number.

1809909529381 is a deficient number, since it is larger than the sum of its proper divisors (1).

1809909529381 is an equidigital number, since it uses as much as digits as its factorization.

1809909529381 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 12597120, while the sum is 64.

The spelling of 1809909529381 in words is "one trillion, eight hundred nine billion, nine hundred nine million, five hundred twenty-nine thousand, three hundred eighty-one".