644143630 has 16 divisors (see below), whose sum is σ = 1248647904. Its totient is φ = 237837600.

The previous prime is 644143627. The next prime is 644143639. The reversal of 644143630 is 36341446.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 644143592 and 644143601.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644143639) 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, 2477346 + ... + 2477605.

It is an arithmetic number, because the mean of its divisors is an integer number (78040494).

Almost surely, 2^644143630 is an apocalyptic number.

644143630 is a deficient number, since it is larger than the sum of its proper divisors (604504274).

644143630 is a wasteful number, since it uses less digits than its factorization.

644143630 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4954971.

The product of its (nonzero) digits is 20736, while the sum is 31.

The square root of 644143630 is about 25379.9848305707. The cubic root of 644143630 is about 863.6297058263.

The spelling of 644143630 in words is "six hundred forty-four million, one hundred forty-three thousand, six hundred thirty".