1645259549 has 4 divisors (see below), whose sum is σ = 1676302236. Its totient is φ = 1614216864.

The previous prime is 1645259543. The next prime is 1645259591. The reversal of 1645259549 is 9459525461.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 820536025 + 824723524 = 28645^2 + 28718^2 .

It is a cyclic number.

It is not a de Polignac number, because 1645259549 - 2¹² = 1645255453 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1645259497 and 1645259506.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1645259543) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15521264 + ... + 15521369.

It is an arithmetic number, because the mean of its divisors is an integer number (419075559).

Almost surely, 2^1645259549 is an apocalyptic number.

It is an amenable number.

1645259549 is a deficient number, since it is larger than the sum of its proper divisors (31042687).

1645259549 is an equidigital number, since it uses as much as digits as its factorization.

1645259549 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31042686.

The product of its digits is 1944000, while the sum is 50.

The square root of 1645259549 is about 40561.7991341607. The cubic root of 1645259549 is about 1180.5330228591.

The spelling of 1645259549 in words is "one billion, six hundred forty-five million, two hundred fifty-nine thousand, five hundred forty-nine".