644420470 has 32 divisors (see below), whose sum is σ = 1191236256. Its totient is φ = 250905600.

The previous prime is 644420443. The next prime is 644420471. The reversal of 644420470 is 74024446.

644420470 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a super-3 number, since 3×644420470³ (a number of 27 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644420471) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 53725 + ... + 64615.

It is an arithmetic number, because the mean of its divisors is an integer number (37226133).

Almost surely, 2^644420470 is an apocalyptic number.

644420470 is a deficient number, since it is larger than the sum of its proper divisors (546815786).

644420470 is a wasteful number, since it uses less digits than its factorization.

644420470 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11056.

The product of its (nonzero) digits is 21504, while the sum is 31.

The square root of 644420470 is about 25385.4381486710. The cubic root of 644420470 is about 863.7534116755.

The spelling of 644420470 in words is "six hundred forty-four million, four hundred twenty thousand, four hundred seventy".