1645645489 has 4 divisors (see below), whose sum is σ = 1645898560. Its totient is φ = 1645392420.

The previous prime is 1645645487. The next prime is 1645645517. The reversal of 1645645489 is 9845465461.

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 1645645489 - 2¹ = 1645645487 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1645645487) 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, 116517 + ... + 129874.

It is an arithmetic number, because the mean of its divisors is an integer number (411474640).

Almost surely, 2^1645645489 is an apocalyptic number.

It is an amenable number.

1645645489 is a deficient number, since it is larger than the sum of its proper divisors (253071).

1645645489 is an equidigital number, since it uses as much as digits as its factorization.

1645645489 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 253070.

The product of its digits is 4147200, while the sum is 52.

The square root of 1645645489 is about 40566.5562871684. The cubic root of 1645645489 is about 1180.6253242621.

The spelling of 1645645489 in words is "one billion, six hundred forty-five million, six hundred forty-five thousand, four hundred eighty-nine".