645537684 has 96 divisors (see below), whose sum is σ = 1673118720. Its totient is φ = 192096000.

The previous prime is 645537679. The next prime is 645537689. The reversal of 645537684 is 486735546.

It is an interprime number because it is at equal distance from previous prime (645537679) and next prime (645537689).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645537689) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2770432 + ... + 2770664.

It is an arithmetic number, because the mean of its divisors is an integer number (17428320).

Almost surely, 2^645537684 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 645537684, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (836559360).

645537684 is an abundant number, since it is smaller than the sum of its proper divisors (1027581036).

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

645537684 is a wasteful number, since it uses less digits than its factorization.

645537684 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 541 (or 539 counting only the distinct ones).

The product of its digits is 2419200, while the sum is 48.

The square root of 645537684 is about 25407.4336366348. The cubic root of 645537684 is about 864.2522786536.

The spelling of 645537684 in words is "six hundred forty-five million, five hundred thirty-seven thousand, six hundred eighty-four".