645738750 has 240 divisors, whose sum is σ = 1928195280. Its totient is φ = 160056000.

The previous prime is 645738749. The next prime is 645738757. The reversal of 645738750 is 57837546.

645738750 is a `hidden beast` number, since 6 + 4 + 573 + 8 + 75 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 645738696 and 645738705.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645738757) by changing a digit.

It is a polite number, since it can be written in 119 ways as a sum of consecutive naturals, for example, 12183724 + ... + 12183776.

It is an arithmetic number, because the mean of its divisors is an integer number (8034147).

Almost surely, 2^645738750 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 645738750, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (964097640).

645738750 is an abundant number, since it is smaller than the sum of its proper divisors (1282456530).

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

645738750 is a wasteful number, since it uses less digits than its factorization.

645738750 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 122 (or 82 counting only the distinct ones).

The product of its (nonzero) digits is 705600, while the sum is 45.

The square root of 645738750 is about 25411.3901626810. The cubic root of 645738750 is about 864.3419990600.

The spelling of 645738750 in words is "six hundred forty-five million, seven hundred thirty-eight thousand, seven hundred fifty".