644022626 has 16 divisors (see below), whose sum is σ = 1055874624. Its totient is φ = 292803984.

The previous prime is 644022581. The next prime is 644022649. The reversal of 644022626 is 626220446.

It is a junction number, because it is equal to n+sod(n) for n = 644022592 and 644022601.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 183110 + ... + 186593.

It is an arithmetic number, because the mean of its divisors is an integer number (65992164).

Almost surely, 2^644022626 is an apocalyptic number.

644022626 is a deficient number, since it is larger than the sum of its proper divisors (411851998).

644022626 is a wasteful number, since it uses less digits than its factorization.

644022626 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 369785.

The product of its (nonzero) digits is 27648, while the sum is 32.

The square root of 644022626 is about 25377.6008716348. The cubic root of 644022626 is about 863.5756241027.

The spelling of 644022626 in words is "six hundred forty-four million, twenty-two thousand, six hundred twenty-six".