645424244 has 24 divisors (see below), whose sum is σ = 1212325128. Its totient is φ = 299566080.

The previous prime is 645424237. The next prime is 645424259. The reversal of 645424244 is 442424546.

It can be written as a sum of positive squares in 4 ways, for example, as 37210000 + 608214244 = 6100^2 + 24662^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 60047 + ... + 69974.

It is an arithmetic number, because the mean of its divisors is an integer number (50513547).

Almost surely, 2^645424244 is an apocalyptic number.

It is an amenable number.

645424244 is a deficient number, since it is larger than the sum of its proper divisors (566900884).

645424244 is a wasteful number, since it uses less digits than its factorization.

645424244 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 130115 (or 130113 counting only the distinct ones).

The product of its digits is 122880, while the sum is 35.

The square root of 645424244 is about 25405.2011210303. The cubic root of 645424244 is about 864.2016508207.

It can be divided in two parts, 64542 and 4244, that added together give a palindrome (68786).

The spelling of 645424244 in words is "six hundred forty-five million, four hundred twenty-four thousand, two hundred forty-four".