646251 has 4 divisors (see below), whose sum is σ = 861672. Its totient is φ = 430832.

The previous prime is 646237. The next prime is 646253. The reversal of 646251 is 152646.

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 646251 - 2⁹ = 645739 is a prime.

It is a D-number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 646251.

It is not an unprimeable number, because it can be changed into a prime (646253) 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, 107706 + ... + 107711.

It is an arithmetic number, because the mean of its divisors is an integer number (215418).

2⁶⁴⁶²⁵¹ is an apocalyptic number.

646251 is a deficient number, since it is larger than the sum of its proper divisors (215421).

646251 is a wasteful number, since it uses less digits than its factorization.

646251 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 215420.

The product of its digits is 1440, while the sum is 24.

The square root of 646251 is about 803.8973815108. The cubic root of 646251 is about 86.4570492995.

Adding to 646251 its reverse (152646), we get a palindrome (798897).

The spelling of 646251 in words is "six hundred forty-six thousand, two hundred fifty-one".