645804541 has 4 divisors (see below), whose sum is σ = 652074592. Its totient is φ = 639534492.

The previous prime is 645804479. The next prime is 645804553. The reversal of 645804541 is 145408546.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 145408546 = 2 ⋅72704273.

It is a cyclic number.

It is not a de Polignac number, because 645804541 - 2¹⁵ = 645771773 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 645804541.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645804641) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3134871 + ... + 3135076.

It is an arithmetic number, because the mean of its divisors is an integer number (163018648).

Almost surely, 2^645804541 is an apocalyptic number.

It is an amenable number.

645804541 is a deficient number, since it is larger than the sum of its proper divisors (6270051).

645804541 is a wasteful number, since it uses less digits than its factorization.

645804541 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6270050.

The product of its (nonzero) digits is 76800, while the sum is 37.

The square root of 645804541 is about 25412.6846476322. The cubic root of 645804541 is about 864.3713525167.

The spelling of 645804541 in words is "six hundred forty-five million, eight hundred four thousand, five hundred forty-one".