643251460 has 108 divisors (see below), whose sum is σ = 1488858084. Its totient is φ = 233326080.

The previous prime is 643251443. The next prime is 643251463. The reversal of 643251460 is 64152346.

It can be written as a sum of positive squares in 6 ways, for example, as 159163456 + 484088004 = 12616^2 + 22002^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643251463) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 12136794 + ... + 12136846.

It is an arithmetic number, because the mean of its divisors is an integer number (13785723).

Almost surely, 2^643251460 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 643251460, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (744429042).

643251460 is an abundant number, since it is smaller than the sum of its proper divisors (845606624).

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

643251460 is a wasteful number, since it uses less digits than its factorization.

643251460 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 182 (or 120 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 31.

The square root of 643251460 is about 25362.4024887233. The cubic root of 643251460 is about 863.2307986668.

The spelling of 643251460 in words is "six hundred forty-three million, two hundred fifty-one thousand, four hundred sixty".