1645107823 has 4 divisors (see below), whose sum is σ = 1647137128. Its totient is φ = 1643078520.

The previous prime is 1645107791. The next prime is 1645107829. The reversal of 1645107823 is 3287015461.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 3287015461 = 709 ⋅4636129.

It is a cyclic number.

It is not a de Polignac number, because 1645107823 - 2⁵ = 1645107791 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1645107829) 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, 1013436 + ... + 1015057.

It is an arithmetic number, because the mean of its divisors is an integer number (411784282).

Almost surely, 2^1645107823 is an apocalyptic number.

1645107823 is a deficient number, since it is larger than the sum of its proper divisors (2029305).

1645107823 is an equidigital number, since it uses as much as digits as its factorization.

1645107823 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2029304.

The product of its (nonzero) digits is 40320, while the sum is 37.

The square root of 1645107823 is about 40559.9287844542. The cubic root of 1645107823 is about 1180.4967321191.

The spelling of 1645107823 in words is "one billion, six hundred forty-five million, one hundred seven thousand, eight hundred twenty-three".