645523222 has 4 divisors (see below), whose sum is σ = 968284836. Its totient is φ = 322761610.

The previous prime is 645523213. The next prime is 645523231. The reversal of 645523222 is 222325546.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 222325546 = 2 ⋅111162773.

It is an interprime number because it is at equal distance from previous prime (645523213) and next prime (645523231).

It is a super-2 number, since 2×645523222² = 833400460282522568, which contains 22 as substring.

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 congruent number.

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 161380804 + ... + 161380807.

It is an arithmetic number, because the mean of its divisors is an integer number (242071209).

Almost surely, 2^645523222 is an apocalyptic number.

645523222 is a deficient number, since it is larger than the sum of its proper divisors (322761614).

645523222 is a wasteful number, since it uses less digits than its factorization.

645523222 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 322761613.

The product of its digits is 28800, while the sum is 31.

The square root of 645523222 is about 25407.1490332938. The cubic root of 645523222 is about 864.2458246489.

Adding to 645523222 its reverse (222325546), we get a palindrome (867848768).

The spelling of 645523222 in words is "six hundred forty-five million, five hundred twenty-three thousand, two hundred twenty-two".