645033135221 has 16 divisors (see below), whose sum is σ = 670135323648. Its totient is φ = 620207539200.

The previous prime is 645033135211. The next prime is 645033135269. The reversal of 645033135221 is 122531330546.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 645033135221 - 2⁶ = 645033135157 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 (645033135211) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4700816 + ... + 4836086.

It is an arithmetic number, because the mean of its divisors is an integer number (41883457728).

Almost surely, 2^645033135221 is an apocalyptic number.

It is an amenable number.

645033135221 is a deficient number, since it is larger than the sum of its proper divisors (25102188427).

645033135221 is a wasteful number, since it uses less digits than its factorization.

645033135221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 136292.

The product of its (nonzero) digits is 64800, while the sum is 35.

Adding to 645033135221 its reverse (122531330546), we get a palindrome (767564465767).

The spelling of 645033135221 in words is "six hundred forty-five billion, thirty-three million, one hundred thirty-five thousand, two hundred twenty-one".