644722002 has 48 divisors (see below), whose sum is σ = 1425790080. Its totient is φ = 210506400.

The previous prime is 644721943. The next prime is 644722019. The reversal of 644722002 is 200227446.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 184552 + ... + 188012.

It is an arithmetic number, because the mean of its divisors is an integer number (29703960).

Almost surely, 2^644722002 is an apocalyptic number.

644722002 is an abundant number, since it is smaller than the sum of its proper divisors (781068078).

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

644722002 is a wasteful number, since it uses less digits than its factorization.

644722002 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3679 (or 3676 counting only the distinct ones).

The product of its (nonzero) digits is 5376, while the sum is 27.

The square root of 644722002 is about 25391.3765282625. The cubic root of 644722002 is about 863.8881108323. Note that the first 3 decimals are identical.

Adding to 644722002 its reverse (200227446), we get a palindrome (844949448).

The spelling of 644722002 in words is "six hundred forty-four million, seven hundred twenty-two thousand, two".