643215 has 16 divisors (see below), whose sum is σ = 1039968. Its totient is φ = 339456.

The previous prime is 643213. The next prime is 643217. The reversal of 643215 is 512346.

It is a happy number.

643215 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (643213) and next prime (643217).

It is not a de Polignac number, because 643215 - 2¹ = 643213 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 643191 and 643200.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643213) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1899 + ... + 2211.

It is an arithmetic number, because the mean of its divisors is an integer number (64998).

2⁶⁴³²¹⁵ is an apocalyptic number.

643215 is a deficient number, since it is larger than the sum of its proper divisors (396753).

643215 is a wasteful number, since it uses less digits than its factorization.

643215 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 458.

The product of its digits is 720, while the sum is 21.

The square root of 643215 is about 802.0068578260. The cubic root of 643215 is about 86.3214488825.

It can be divided in two parts, 643 and 215, that added together give a palindrome (858).

The spelling of 643215 in words is "six hundred forty-three thousand, two hundred fifteen".