644517066 has 16 divisors (see below), whose sum is σ = 1296237600. Its totient is φ = 213638448.

The previous prime is 644517061. The next prime is 644517091. The reversal of 644517066 is 660715446.

It is not an unprimeable number, because it can be changed into a prime (644517061) 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, 298981 + ... + 301128.

It is an arithmetic number, because the mean of its divisors is an integer number (81014850).

Almost surely, 2^644517066 is an apocalyptic number.

644517066 is an abundant number, since it is smaller than the sum of its proper divisors (651720534).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

644517066 is a wasteful number, since it uses less digits than its factorization.

644517066 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 600293.

The product of its (nonzero) digits is 120960, while the sum is 39.

The square root of 644517066 is about 25387.3406641972. The cubic root of 644517066 is about 863.7965672237.

It can be divided in two parts, 64451 and 7066, that added together give a palindrome (71517).

The spelling of 644517066 in words is "six hundred forty-four million, five hundred seventeen thousand, sixty-six".