1820009129 has 4 divisors (see below), whose sum is σ = 1824232320. Its totient is φ = 1815785940.

The previous prime is 1820009111. The next prime is 1820009131. The reversal of 1820009129 is 9219000281.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 9219000281 = 379 ⋅24324539.

It is a cyclic number.

It is not a de Polignac number, because 1820009129 - 2²⁰ = 1818960553 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1820009095 and 1820009104.

It is not an unprimeable number, because it can be changed into a prime (1820009329) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2110949 + ... + 2111810.

It is an arithmetic number, because the mean of its divisors is an integer number (456058080).

Almost surely, 2^1820009129 is an apocalyptic number.

It is an amenable number.

1820009129 is a deficient number, since it is larger than the sum of its proper divisors (4223191).

1820009129 is an equidigital number, since it uses as much as digits as its factorization.

1820009129 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4223190.

The product of its (nonzero) digits is 2592, while the sum is 32.

The square root of 1820009129 is about 42661.5650087992. The cubic root of 1820009129 is about 1220.9311911101.

The spelling of 1820009129 in words is "one billion, eight hundred twenty million, nine thousand, one hundred twenty-nine".