644226330 has 32 divisors (see below), whose sum is σ = 1686702528. Its totient is φ = 156176000.

The previous prime is 644226313. The next prime is 644226337. The reversal of 644226330 is 33622446.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is not an unprimeable number, because it can be changed into a prime (644226337) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 975771 + ... + 976430.

It is an arithmetic number, because the mean of its divisors is an integer number (52709454).

Almost surely, 2^644226330 is an apocalyptic number.

644226330 is an abundant number, since it is smaller than the sum of its proper divisors (1042476198).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

644226330 is a wasteful number, since it uses less digits than its factorization.

644226330 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1952222.

The product of its (nonzero) digits is 20736, while the sum is 30.

The square root of 644226330 is about 25381.6140148730. The cubic root of 644226330 is about 863.6666640020. Note that the first 5 decimals are identical.

Adding to 644226330 its reverse (33622446), we get a palindrome (677848776).

The spelling of 644226330 in words is "six hundred forty-four million, two hundred twenty-six thousand, three hundred thirty".