1645256643 has 8 divisors (see below), whose sum is σ = 2200685328. Its totient is φ = 1093332864.

The previous prime is 1645256629. The next prime is 1645256647. The reversal of 1645256643 is 3466525461.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1645256643 - 2¹² = 1645252547 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1645256595 and 1645256604.

It is not an unprimeable number, because it can be changed into a prime (1645256647) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 875130 + ... + 877007.

It is an arithmetic number, because the mean of its divisors is an integer number (275085666).

Almost surely, 2^1645256643 is an apocalyptic number.

1645256643 is a deficient number, since it is larger than the sum of its proper divisors (555428685).

1645256643 is a wasteful number, since it uses less digits than its factorization.

1645256643 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1752453.

The product of its digits is 518400, while the sum is 42.

The square root of 1645256643 is about 40561.7633122624. The cubic root of 1645256643 is about 1180.5323278055.

The spelling of 1645256643 in words is "one billion, six hundred forty-five million, two hundred fifty-six thousand, six hundred forty-three".