644226106 has 4 divisors (see below), whose sum is σ = 966339162. Its totient is φ = 322113052.

The previous prime is 644226061. The next prime is 644226109. The reversal of 644226106 is 601622446.

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

It can be written as a sum of positive squares in only one way, i.e., 436433881 + 207792225 = 20891^2 + 14415^2 .

It is not an unprimeable number, because it can be changed into a prime (644226109) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 161056525 + ... + 161056528.

Almost surely, 2^644226106 is an apocalyptic number.

644226106 is a deficient number, since it is larger than the sum of its proper divisors (322113056).

644226106 is a wasteful number, since it uses less digits than its factorization.

644226106 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 322113055.

The product of its (nonzero) digits is 13824, while the sum is 31.

The square root of 644226106 is about 25381.6096022297. The cubic root of 644226106 is about 863.6665639019. Note that the first 3 decimals are identical.

The spelling of 644226106 in words is "six hundred forty-four million, two hundred twenty-six thousand, one hundred six".