1820398689 has 12 divisors (see below), whose sum is σ = 2685411456. Its totient is φ = 1187777592.

The previous prime is 1820398669. The next prime is 1820398747. The reversal of 1820398689 is 9868930281.

It is a happy number.

It is not a de Polignac number, because 1820398689 - 2¹⁶ = 1820333153 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1820398609) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2151349 + ... + 2152194.

It is an arithmetic number, because the mean of its divisors is an integer number (223784288).

Almost surely, 2^1820398689 is an apocalyptic number.

It is an amenable number.

1820398689 is a deficient number, since it is larger than the sum of its proper divisors (865012767).

1820398689 is a wasteful number, since it uses less digits than its factorization.

1820398689 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4303596 (or 4303593 counting only the distinct ones).

The product of its (nonzero) digits is 1492992, while the sum is 54.

The square root of 1820398689 is about 42666.1304666828. The cubic root of 1820398689 is about 1221.0182954395.

The spelling of 1820398689 in words is "one billion, eight hundred twenty million, three hundred ninety-eight thousand, six hundred eighty-nine".