644074042 has 16 divisors (see below), whose sum is σ = 997899264. Its totient is φ = 311454000.

The previous prime is 644074009. The next prime is 644074049. The reversal of 644074042 is 240470446.

644074042 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (31).

It is a junction number, because it is equal to n+sod(n) for n = 644073995 and 644074013.

It is not an unprimeable number, because it can be changed into a prime (644074049) 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, 175567 + ... + 179197.

It is an arithmetic number, because the mean of its divisors is an integer number (62368704).

Almost surely, 2^644074042 is an apocalyptic number.

644074042 is a gapful number since it is divisible by the number (62) formed by its first and last digit.

644074042 is a deficient number, since it is larger than the sum of its proper divisors (353825222).

644074042 is a wasteful number, since it uses less digits than its factorization.

644074042 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6525.

The product of its (nonzero) digits is 21504, while the sum is 31.

The square root of 644074042 is about 25378.6138707377. The cubic root of 644074042 is about 863.5986048805.

The spelling of 644074042 in words is "six hundred forty-four million, seventy-four thousand, forty-two".