644211386 has 16 divisors (see below), whose sum is σ = 1189313664. Its totient is φ = 254852784.

The previous prime is 644211367. The next prime is 644211391. The reversal of 644211386 is 683112446.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1769630 + ... + 1769993.

It is an arithmetic number, because the mean of its divisors is an integer number (74332104).

Almost surely, 2^644211386 is an apocalyptic number.

644211386 is a deficient number, since it is larger than the sum of its proper divisors (545102278).

644211386 is a wasteful number, since it uses less digits than its factorization.

644211386 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3539645.

The product of its digits is 27648, while the sum is 35.

The square root of 644211386 is about 25381.3196268437. The cubic root of 644211386 is about 863.6599858446.

The spelling of 644211386 in words is "six hundred forty-four million, two hundred eleven thousand, three hundred eighty-six".