644022242 has 8 divisors (see below), whose sum is σ = 967342800. Its totient is φ = 321574644.

The previous prime is 644022217. The next prime is 644022263. The reversal of 644022242 is 242220446.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 216392 + ... + 219347.

It is an arithmetic number, because the mean of its divisors is an integer number (120917850).

Almost surely, 2^644022242 is an apocalyptic number.

644022242 is a deficient number, since it is larger than the sum of its proper divisors (323320558).

644022242 is a wasteful number, since it uses less digits than its factorization.

644022242 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 436480.

The product of its (nonzero) digits is 6144, while the sum is 26.

The square root of 644022242 is about 25377.5933059067. The cubic root of 644022242 is about 863.5754524663.

Adding to 644022242 its reverse (242220446), we get a palindrome (886242688).

It can be divided in two parts, 6440 and 22242, that added together give a palindrome (28682).

The spelling of 644022242 in words is "six hundred forty-four million, twenty-two thousand, two hundred forty-two".