645278244 has 48 divisors (see below), whose sum is σ = 1643709312. Its totient is φ = 195823872.

The previous prime is 645278243. The next prime is 645278269. The reversal of 645278244 is 442872546.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 645278196 and 645278205.

It is not an unprimeable number, because it can be changed into a prime (645278243) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 16944 + ... + 39719.

It is an arithmetic number, because the mean of its divisors is an integer number (34243944).

Almost surely, 2^645278244 is an apocalyptic number.

It is an amenable number.

645278244 is an abundant number, since it is smaller than the sum of its proper divisors (998431068).

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

645278244 is a wasteful number, since it uses less digits than its factorization.

645278244 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 56756 (or 56754 counting only the distinct ones).

The product of its digits is 430080, while the sum is 42.

The square root of 645278244 is about 25402.3275311535. The cubic root of 645278244 is about 864.1364828545.

It can be divided in two parts, 64527 and 8244, that added together give a triangular number (72771 = T₃₈₁).

The spelling of 645278244 in words is "six hundred forty-five million, two hundred seventy-eight thousand, two hundred forty-four".