1645354521 has 12 divisors (see below), whose sum is σ = 2427190272. Its totient is φ = 1073564376.

The previous prime is 1645354511. The next prime is 1645354523. The reversal of 1645354521 is 1254535461.

1645354521 is a `hidden beast` number, since 1 + 64 + 53 + 545 + 2 + 1 = 666.

It is not a de Polignac number, because 1645354521 - 2⁷ = 1645354393 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1645354523) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1944441 + ... + 1945286.

It is an arithmetic number, because the mean of its divisors is an integer number (202265856).

Almost surely, 2^1645354521 is an apocalyptic number.

It is an amenable number.

1645354521 is a deficient number, since it is larger than the sum of its proper divisors (781835751).

1645354521 is a wasteful number, since it uses less digits than its factorization.

1645354521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3889780 (or 3889777 counting only the distinct ones).

The product of its digits is 72000, while the sum is 36.

The square root of 1645354521 is about 40562.9698247059. The cubic root of 1645354521 is about 1180.5557376997. Note that the first 3 decimals are identical.

Adding to 1645354521 its reverse (1254535461), we get a palindrome (2899889982).

The spelling of 1645354521 in words is "one billion, six hundred forty-five million, three hundred fifty-four thousand, five hundred twenty-one".