645206143 has 4 divisors (see below), whose sum is σ = 673258608. Its totient is φ = 617153680.

The previous prime is 645206137. The next prime is 645206167. The reversal of 645206143 is 341602546.

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

It is a cyclic number.

It is not a de Polignac number, because 645206143 - 2¹³ = 645197951 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645206173) 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, 14026198 + ... + 14026243.

It is an arithmetic number, because the mean of its divisors is an integer number (168314652).

Almost surely, 2^645206143 is an apocalyptic number.

645206143 is a deficient number, since it is larger than the sum of its proper divisors (28052465).

645206143 is a wasteful number, since it uses less digits than its factorization.

645206143 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28052464.

The product of its (nonzero) digits is 17280, while the sum is 31.

The square root of 645206143 is about 25400.9083105309. The cubic root of 645206143 is about 864.1042965194.

Adding to 645206143 its reverse (341602546), we get a palindrome (986808689).

The spelling of 645206143 in words is "six hundred forty-five million, two hundred six thousand, one hundred forty-three".