1645242469 has 4 divisors (see below), whose sum is σ = 1771799596. Its totient is φ = 1518685344.

The previous prime is 1645242461. The next prime is 1645242497. The reversal of 1645242469 is 9642425461.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 9642425461 = 67447 ⋅142963.

It can be written as a sum of positive squares in 2 ways, for example, as 496710369 + 1148532100 = 22287^2 + 33890^2 .

It is a cyclic number.

It is not a de Polignac number, because 1645242469 - 2³ = 1645242461 is a prime.

It is a super-2 number, since 2×1645242469² = 5413645563602431922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1645242461) 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 3 ways as a sum of consecutive naturals, for example, 63278544 + ... + 63278569.

It is an arithmetic number, because the mean of its divisors is an integer number (442949899).

Almost surely, 2^1645242469 is an apocalyptic number.

It is an amenable number.

1645242469 is a deficient number, since it is larger than the sum of its proper divisors (126557127).

1645242469 is a wasteful number, since it uses less digits than its factorization.

1645242469 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 126557126.

The product of its digits is 414720, while the sum is 43.

The square root of 1645242469 is about 40561.5885906852. The cubic root of 1645242469 is about 1180.5289376732.

The spelling of 1645242469 in words is "one billion, six hundred forty-five million, two hundred forty-two thousand, four hundred sixty-nine".