644822986 has 32 divisors (see below), whose sum is σ = 1041320448. Its totient is φ = 298742400.

The previous prime is 644822921. The next prime is 644822987. The reversal of 644822986 is 689228446.

It is not an unprimeable number, because it can be changed into a prime (644822987) 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, 216886 + ... + 219838.

It is an arithmetic number, because the mean of its divisors is an integer number (32541264).

Almost surely, 2^644822986 is an apocalyptic number.

644822986 is a deficient number, since it is larger than the sum of its proper divisors (396497462).

644822986 is a wasteful number, since it uses less digits than its factorization.

644822986 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3126.

The product of its digits is 1327104, while the sum is 49.

The square root of 644822986 is about 25393.3649995427. The cubic root of 644822986 is about 863.9332126087.

The spelling of 644822986 in words is "six hundred forty-four million, eight hundred twenty-two thousand, nine hundred eighty-six".