645449706 has 48 divisors (see below), whose sum is σ = 1540468800. Its totient is φ = 193685760.

The previous prime is 645449699. The next prime is 645449767. The reversal of 645449706 is 607944546.

It is a Curzon number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4570 + ... + 36218.

It is an arithmetic number, because the mean of its divisors is an integer number (32093100).

Almost surely, 2^645449706 is an apocalyptic number.

645449706 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 645449706, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (770234400).

645449706 is an abundant number, since it is smaller than the sum of its proper divisors (895019094).

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

645449706 is a wasteful number, since it uses less digits than its factorization.

645449706 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31771 (or 31768 counting only the distinct ones).

The product of its (nonzero) digits is 725760, while the sum is 45.

The square root of 645449706 is about 25405.7022339474. The cubic root of 645449706 is about 864.2130149290.

The spelling of 645449706 in words is "six hundred forty-five million, four hundred forty-nine thousand, seven hundred six".