643252481 has 8 divisors (see below), whose sum is σ = 657306624. Its totient is φ = 629213760.

The previous prime is 643252471. The next prime is 643252541. The reversal of 643252481 is 184252346.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-643252481 is a prime.

It is a super-2 number, since 2×643252481² = 827547508625310722, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (643252471) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 130736 + ... + 135566.

It is an arithmetic number, because the mean of its divisors is an integer number (82163328).

Almost surely, 2^643252481 is an apocalyptic number.

It is an amenable number.

643252481 is a deficient number, since it is larger than the sum of its proper divisors (14054143).

643252481 is a wasteful number, since it uses less digits than its factorization.

643252481 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7711.

The product of its digits is 46080, while the sum is 35.

The square root of 643252481 is about 25362.4226169347. The cubic root of 643252481 is about 863.2312553872.

The spelling of 643252481 in words is "six hundred forty-three million, two hundred fifty-two thousand, four hundred eighty-one".