645898734 has 72 divisors (see below), whose sum is σ = 1529601840. Its totient is φ = 196874496.

The previous prime is 645898727. The next prime is 645898741. The reversal of 645898734 is 437898546.

It is an interprime number because it is at equal distance from previous prime (645898727) and next prime (645898741).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 342807 + ... + 344685.

It is an arithmetic number, because the mean of its divisors is an integer number (21244470).

Almost surely, 2^645898734 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 645898734, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (764800920).

645898734 is an abundant number, since it is smaller than the sum of its proper divisors (883703106).

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

645898734 is a wasteful number, since it uses less digits than its factorization.

645898734 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2026 (or 2010 counting only the distinct ones).

The product of its digits is 5806080, while the sum is 54.

The square root of 645898734 is about 25414.5378474605. The cubic root of 645898734 is about 864.4133744019.

The spelling of 645898734 in words is "six hundred forty-five million, eight hundred ninety-eight thousand, seven hundred thirty-four".