644248534 has 8 divisors (see below), whose sum is σ = 968680440. Its totient is φ = 321355056.

The previous prime is 644248531. The next prime is 644248559. The reversal of 644248534 is 435842446.

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

It is a super-2 number, since 2×644248534² = 830112347122298312, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644248531) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 383559 + ... + 385234.

It is an arithmetic number, because the mean of its divisors is an integer number (121085055).

Almost surely, 2^644248534 is an apocalyptic number.

644248534 is a deficient number, since it is larger than the sum of its proper divisors (324431906).

644248534 is a wasteful number, since it uses less digits than its factorization.

644248534 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 769214.

The product of its digits is 368640, while the sum is 40.

The square root of 644248534 is about 25382.0514143361. The cubic root of 644248534 is about 863.6765863090.

The spelling of 644248534 in words is "six hundred forty-four million, two hundred forty-eight thousand, five hundred thirty-four".