644883081 has 8 divisors (see below), whose sum is σ = 868357824. Its totient is φ = 425665200.

The previous prime is 644883079. The next prime is 644883091. The reversal of 644883081 is 180388446.

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

It is not a de Polignac number, because 644883081 - 2¹ = 644883079 is a prime.

It is a super-2 number, since 2×644883081² = 831748376320105122, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (644883011) by changing a digit.

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, 1063861 + ... + 1064466.

It is an arithmetic number, because the mean of its divisors is an integer number (108544728).

Almost surely, 2^644883081 is an apocalyptic number.

It is an amenable number.

644883081 is a deficient number, since it is larger than the sum of its proper divisors (223474743).

644883081 is a wasteful number, since it uses less digits than its factorization.

644883081 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2128431.

The product of its (nonzero) digits is 147456, while the sum is 42.

The square root of 644883081 is about 25394.5482535130. The cubic root of 644883081 is about 863.9600501826.

The spelling of 644883081 in words is "six hundred forty-four million, eight hundred eighty-three thousand, eighty-one".