644022461 has 8 divisors (see below), whose sum is σ = 683258880. Its totient is φ = 605320128.

The previous prime is 644022433. The next prime is 644022473. The reversal of 644022461 is 164220446.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 644022461 - 2²² = 639828157 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644022061) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 131036 + ... + 135861.

It is an arithmetic number, because the mean of its divisors is an integer number (85407360).

Almost surely, 2^644022461 is an apocalyptic number.

It is an amenable number.

644022461 is a deficient number, since it is larger than the sum of its proper divisors (39236419).

644022461 is a wasteful number, since it uses less digits than its factorization.

644022461 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 267043.

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

The square root of 644022461 is about 25377.5976207363. The cubic root of 644022461 is about 863.5755503527.

The spelling of 644022461 in words is "six hundred forty-four million, twenty-two thousand, four hundred sixty-one".