1645408489 has 2 divisors, whose sum is σ = 1645408490. Its totient is φ = 1645408488.

The previous prime is 1645408451. The next prime is 1645408511. The reversal of 1645408489 is 9848045461.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1136229264 + 509179225 = 33708^2 + 22565^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1645408489 is a prime.

It is not a weakly prime, because it can be changed into another prime (1645408439) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 822704244 + 822704245.

It is an arithmetic number, because the mean of its divisors is an integer number (822704245).

Almost surely, 2^1645408489 is an apocalyptic number.

It is an amenable number.

1645408489 is a deficient number, since it is larger than the sum of its proper divisors (1).

1645408489 is an equidigital number, since it uses as much as digits as its factorization.

1645408489 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1105920, while the sum is 49.

The square root of 1645408489 is about 40563.6350565380. The cubic root of 1645408489 is about 1180.5686450569.

The spelling of 1645408489 in words is "one billion, six hundred forty-five million, four hundred eight thousand, four hundred eighty-nine".