1820749389 has 4 divisors (see below), whose sum is σ = 2427665856. Its totient is φ = 1213832924.

The previous prime is 1820749379. The next prime is 1820749493. The reversal of 1820749389 is 9839470281.

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.

It is a cyclic number.

It is not a de Polignac number, because 1820749389 - 2⁹ = 1820748877 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1820749339) 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, 303458229 + ... + 303458234.

It is an arithmetic number, because the mean of its divisors is an integer number (606916464).

Almost surely, 2^1820749389 is an apocalyptic number.

It is an amenable number.

1820749389 is a deficient number, since it is larger than the sum of its proper divisors (606916467).

1820749389 is an equidigital number, since it uses as much as digits as its factorization.

1820749389 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 606916466.

The product of its (nonzero) digits is 870912, while the sum is 51.

The square root of 1820749389 is about 42670.2400860365. The cubic root of 1820749389 is about 1221.0967001727.

The spelling of 1820749389 in words is "one billion, eight hundred twenty million, seven hundred forty-nine thousand, three hundred eighty-nine".