644053770 has 48 divisors (see below), whose sum is σ = 1691143272. Its totient is φ = 170044800.

The previous prime is 644053759. The next prime is 644053793. The reversal of 644053770 is 77350446.

644053770 is a `hidden beast` number, since 644 + 0 + 5 + 3 + 7 + 7 + 0 = 666.

644053770 is digitally balanced in base 2 and base 6, because in such bases it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 642774609 + 1279161 = 25353^2 + 1131^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 26337 + ... + 44516.

Almost surely, 2^644053770 is an apocalyptic number.

644053770 is an abundant number, since it is smaller than the sum of its proper divisors (1047089502).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

644053770 is a wasteful number, since it uses less digits than its factorization.

644053770 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 70967 (or 70964 counting only the distinct ones).

The product of its (nonzero) digits is 70560, while the sum is 36.

The square root of 644053770 is about 25378.2144761999. The cubic root of 644053770 is about 863.5895442998.

The spelling of 644053770 in words is "six hundred forty-four million, fifty-three thousand, seven hundred seventy".