643487 has 4 divisors (see below), whose sum is σ = 693000. Its totient is φ = 593976.

The previous prime is 643469. The next prime is 643493. The reversal of 643487 is 784346.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 643487 - 2⁸ = 643231 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643457) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 24737 + ... + 24762.

It is an arithmetic number, because the mean of its divisors is an integer number (173250).

2⁶⁴³⁴⁸⁷ is an apocalyptic number.

643487 is a deficient number, since it is larger than the sum of its proper divisors (49513).

643487 is a wasteful number, since it uses less digits than its factorization.

643487 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 49512.

The product of its digits is 16128, while the sum is 32.

The square root of 643487 is about 802.1764145124. The cubic root of 643487 is about 86.3336149157. Note that the first 3 decimals are identical.

The spelling of 643487 in words is "six hundred forty-three thousand, four hundred eighty-seven".