644450131 has 8 divisors (see below), whose sum is σ = 694443680. Its totient is φ = 594516672.

The previous prime is 644450129. The next prime is 644450137. The reversal of 644450131 is 131054446.

644450131 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 644450131 - 2¹ = 644450129 is a prime.

It is a super-2 number, since 2×644450131² = 830631942691834322, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 644450131.

It is not an unprimeable number, because it can be changed into a prime (644450137) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8650 + ... + 36928.

It is an arithmetic number, because the mean of its divisors is an integer number (86805460).

Almost surely, 2^644450131 is an apocalyptic number.

644450131 is a deficient number, since it is larger than the sum of its proper divisors (49993549).

644450131 is a wasteful number, since it uses less digits than its factorization.

644450131 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30045.

The product of its (nonzero) digits is 5760, while the sum is 28.

The square root of 644450131 is about 25386.0223548314. The cubic root of 644450131 is about 863.7666635807.

It can be divided in two parts, 644 and 450131, that added together give a triangular number (450775 = T₉₄₉).

The spelling of 644450131 in words is "six hundred forty-four million, four hundred fifty thousand, one hundred thirty-one".