644799002 has 4 divisors (see below), whose sum is σ = 967198506. Its totient is φ = 322399500.

The previous prime is 644798993. The next prime is 644799011. The reversal of 644799002 is 200997446.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (644798993) and next prime (644799011).

It can be written as a sum of positive squares in only one way, i.e., 466603201 + 178195801 = 21601^2 + 13349^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 161199749 + ... + 161199752.

Almost surely, 2^644799002 is an apocalyptic number.

644799002 is a deficient number, since it is larger than the sum of its proper divisors (322399504).

644799002 is a wasteful number, since it uses less digits than its factorization.

644799002 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 322399503.

The product of its (nonzero) digits is 108864, while the sum is 41.

The square root of 644799002 is about 25392.8927458059. The cubic root of 644799002 is about 863.9225012292.

The spelling of 644799002 in words is "six hundred forty-four million, seven hundred ninety-nine thousand, two".