645748684 has 48 divisors (see below), whose sum is σ = 1358038080. Its totient is φ = 262805760.

The previous prime is 645748681. The next prime is 645748699. The reversal of 645748684 is 486847546.

It is not an unprimeable number, because it can be changed into a prime (645748681) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 43014 + ... + 56050.

It is an arithmetic number, because the mean of its divisors is an integer number (28292460).

Almost surely, 2^645748684 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 645748684, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (679019040).

645748684 is an abundant number, since it is smaller than the sum of its proper divisors (712289396).

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

645748684 is a wasteful number, since it uses less digits than its factorization.

645748684 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13138 (or 13136 counting only the distinct ones).

The product of its digits is 5160960, while the sum is 52.

The square root of 645748684 is about 25411.5856254583. The cubic root of 645748684 is about 864.3464313630.

The spelling of 645748684 in words is "six hundred forty-five million, seven hundred forty-eight thousand, six hundred eighty-four".