644406122 has 8 divisors (see below), whose sum is σ = 966780900. Its totient is φ = 322145824.

The previous prime is 644406079. The next prime is 644406137. The reversal of 644406122 is 221604446.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 644093641 + 312481 = 25379^2 + 559^2 .

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, 12797 + ... + 38112.

Almost surely, 2^644406122 is an apocalyptic number.

644406122 is a deficient number, since it is larger than the sum of its proper divisors (322374778).

644406122 is a wasteful number, since it uses less digits than its factorization.

644406122 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 57240.

The product of its (nonzero) digits is 9216, while the sum is 29.

The square root of 644406122 is about 25385.1555441364. The cubic root of 644406122 is about 863.7470011477.

The spelling of 644406122 in words is "six hundred forty-four million, four hundred six thousand, one hundred twenty-two".