644629313 has 8 divisors (see below), whose sum is σ = 670717800. Its totient is φ = 618798208.

The previous prime is 644629291. The next prime is 644629331. The reversal of 644629313 is 313926446.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 87291649 + 557337664 = 9343^2 + 23608^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 644629313 - 2⁸ = 644629057 is a prime.

It is not an unprimeable number, because it can be changed into a prime (644629343) 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, 59228 + ... + 69261.

It is an arithmetic number, because the mean of its divisors is an integer number (83839725).

Almost surely, 2^644629313 is an apocalyptic number.

It is an amenable number.

644629313 is a deficient number, since it is larger than the sum of its proper divisors (26088487).

644629313 is a wasteful number, since it uses less digits than its factorization.

644629313 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 128691.

The product of its digits is 93312, while the sum is 38.

The square root of 644629313 is about 25389.5512563732. The cubic root of 644629313 is about 863.8467096483.

The spelling of 644629313 in words is "six hundred forty-four million, six hundred twenty-nine thousand, three hundred thirteen".