645121222 has 24 divisors (see below), whose sum is σ = 1017030600. Its totient is φ = 306810720.

The previous prime is 645121207. The next prime is 645121223. The reversal of 645121222 is 222121546.

645121222 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645121223) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 110554 + ... + 116242.

It is an arithmetic number, because the mean of its divisors is an integer number (42376275).

Almost surely, 2^645121222 is an apocalyptic number.

645121222 is a gapful number since it is divisible by the number (62) formed by its first and last digit.

645121222 is a deficient number, since it is larger than the sum of its proper divisors (371909378).

645121222 is a wasteful number, since it uses less digits than its factorization.

645121222 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5812 (or 5781 counting only the distinct ones).

The product of its digits is 1920, while the sum is 25.

The square root of 645121222 is about 25399.2366420725. The cubic root of 645121222 is about 864.0663841812.

Adding to 645121222 its reverse (222121546), we get a palindrome (867242768).

The spelling of 645121222 in words is "six hundred forty-five million, one hundred twenty-one thousand, two hundred twenty-two".