645631133 has 4 divisors (see below), whose sum is σ = 737864160. Its totient is φ = 553398108.

The previous prime is 645631099. The next prime is 645631157. The reversal of 645631133 is 331136546.

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.

It is a cyclic number.

It is not a de Polignac number, because 645631133 - 2¹⁰ = 645630109 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 645631133.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645631193) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 46116503 + ... + 46116516.

It is an arithmetic number, because the mean of its divisors is an integer number (184466040).

Almost surely, 2^645631133 is an apocalyptic number.

It is an amenable number.

645631133 is a deficient number, since it is larger than the sum of its proper divisors (92233027).

645631133 is an equidigital number, since it uses as much as digits as its factorization.

645631133 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 92233026.

The product of its digits is 19440, while the sum is 32.

The square root of 645631133 is about 25409.2725791196. The cubic root of 645631133 is about 864.2939801253.

Adding to 645631133 its reverse (331136546), we get a palindrome (976767679).

The spelling of 645631133 in words is "six hundred forty-five million, six hundred thirty-one thousand, one hundred thirty-three".