643745250 has 96 divisors (see below), whose sum is σ = 1749855744. Its totient is φ = 170762400.

The previous prime is 643745231. The next prime is 643745257. The reversal of 643745250 is 52547346.

643745250 is a `hidden beast` number, since 64 + 3 + 74 + 525 + 0 = 666.

It is not an unprimeable number, because it can be changed into a prime (643745257) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 501109 + ... + 502391.

It is an arithmetic number, because the mean of its divisors is an integer number (18227664).

Almost surely, 2^643745250 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 643745250, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (874927872).

643745250 is an abundant number, since it is smaller than the sum of its proper divisors (1106110494).

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

643745250 is a wasteful number, since it uses less digits than its factorization.

643745250 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1529 (or 1516 counting only the distinct ones).

The product of its (nonzero) digits is 100800, while the sum is 36.

The square root of 643745250 is about 25372.1353062765. The cubic root of 643745250 is about 863.4516276572.

The spelling of 643745250 in words is "six hundred forty-three million, seven hundred forty-five thousand, two hundred fifty".