645420423 has 4 divisors (see below), whose sum is σ = 860560568. Its totient is φ = 430280280.

The previous prime is 645420409. The next prime is 645420449. The reversal of 645420423 is 324024546.

645420423 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 645420423 - 2¹² = 645416327 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 (645420023) 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, 107570068 + ... + 107570073.

It is an arithmetic number, because the mean of its divisors is an integer number (215140142).

Almost surely, 2^645420423 is an apocalyptic number.

645420423 is a deficient number, since it is larger than the sum of its proper divisors (215140145).

645420423 is a wasteful number, since it uses less digits than its factorization.

645420423 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 215140144.

The product of its (nonzero) digits is 23040, while the sum is 30.

The square root of 645420423 is about 25405.1259197824. The cubic root of 645420423 is about 864.1999454199.

Adding to 645420423 its reverse (324024546), we get a palindrome (969444969).

The spelling of 645420423 in words is "six hundred forty-five million, four hundred twenty thousand, four hundred twenty-three".