644263235 has 64 divisors (see below), whose sum is σ = 1038680064. Its totient is φ = 371606400.

The previous prime is 644263231. The next prime is 644263259. The reversal of 644263235 is 532362446.

644263235 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 644263235 - 2² = 644263231 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (35).

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 644263195 and 644263204.

It is not an unprimeable number, because it can be changed into a prime (644263231) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 273332 + ... + 275678.

It is an arithmetic number, because the mean of its divisors is an integer number (16229376).

Almost surely, 2^644263235 is an apocalyptic number.

644263235 is a deficient number, since it is larger than the sum of its proper divisors (394416829).

644263235 is a wasteful number, since it uses less digits than its factorization.

644263235 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2424.

The product of its digits is 103680, while the sum is 35.

The square root of 644263235 is about 25382.3410070860. The cubic root of 644263235 is about 863.6831556231.

The spelling of 644263235 in words is "six hundred forty-four million, two hundred sixty-three thousand, two hundred thirty-five".