644032226 has 4 divisors (see below), whose sum is σ = 966048342. Its totient is φ = 322016112.

The previous prime is 644032219. The next prime is 644032229. The reversal of 644032226 is 622230446.

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., 602751601 + 41280625 = 24551^2 + 6425^2 .

It is not an unprimeable number, because it can be changed into a prime (644032229) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 161008055 + ... + 161008058.

Almost surely, 2^644032226 is an apocalyptic number.

644032226 is a deficient number, since it is larger than the sum of its proper divisors (322016116).

644032226 is a wasteful number, since it uses less digits than its factorization.

644032226 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 322016115.

The product of its (nonzero) digits is 13824, while the sum is 29.

The square root of 644032226 is about 25377.7900141049. The cubic root of 644032226 is about 863.5799149896.

The spelling of 644032226 in words is "six hundred forty-four million, thirty-two thousand, two hundred twenty-six".