644352026 has 8 divisors (see below), whose sum is σ = 974138880. Its totient is φ = 319639068.

The previous prime is 644352013. The next prime is 644352029. The reversal of 644352026 is 620253446.

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

It is a junction number, because it is equal to n+sod(n) for n = 644351983 and 644352001.

It is not an unprimeable number, because it can be changed into a prime (644352029) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1268156 + ... + 1268663.

It is an arithmetic number, because the mean of its divisors is an integer number (121767360).

Almost surely, 2^644352026 is an apocalyptic number.

644352026 is a deficient number, since it is larger than the sum of its proper divisors (329786854).

644352026 is a wasteful number, since it uses less digits than its factorization.

644352026 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2536948.

The product of its (nonzero) digits is 34560, while the sum is 32.

The square root of 644352026 is about 25384.0900171741. The cubic root of 644352026 is about 863.7228307973.

The spelling of 644352026 in words is "six hundred forty-four million, three hundred fifty-two thousand, twenty-six".