645133234224421 has 4 divisors (see below), whose sum is σ = 645928712935744. Its totient is φ = 644337755513100.

The previous prime is 645133234224403. The next prime is 645133234224449. The reversal of 645133234224421 is 124422432331546.

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 a de Polignac number, because none of the positive numbers 2^k-645133234224421 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 (645133234224821) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 397739354445 + ... + 397739356066.

It is an arithmetic number, because the mean of its divisors is an integer number (161482178233936).

Almost surely, 2^{645133234224421} is an apocalyptic number.

It is an amenable number.

645133234224421 is a deficient number, since it is larger than the sum of its proper divisors (795478711323).

645133234224421 is an equidigital number, since it uses as much as digits as its factorization.

645133234224421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 795478711322.

The product of its digits is 3317760, while the sum is 46.

Adding to 645133234224421 its reverse (124422432331546), we get a palindrome (769555666555967).

The spelling of 645133234224421 in words is "six hundred forty-five trillion, one hundred thirty-three billion, two hundred thirty-four million, two hundred twenty-four thousand, four hundred twenty-one".