646145 has 4 divisors (see below), whose sum is σ = 775380. Its totient is φ = 516912.

The previous prime is 646103. The next prime is 646147. The reversal of 646145 is 541646.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 167281 + 478864 = 409^2 + 692^2 .

It is a cyclic number.

It is not a de Polignac number, because 646145 - 2⁸ = 645889 is a prime.

It is a super-2 number, since 2×646145² = 835006722050, which contains 22 as substring.

It is an Ulam number.

It is not an unprimeable number, because it can be changed into a prime (646147) 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, 64610 + ... + 64619.

It is an arithmetic number, because the mean of its divisors is an integer number (193845).

It is a Proth number, since it is equal to 631 ⋅ 2¹⁰ + 1 and 631 < 2¹⁰.

2⁶⁴⁶¹⁴⁵ is an apocalyptic number.

It is an amenable number.

646145 is a deficient number, since it is larger than the sum of its proper divisors (129235).

646145 is a wasteful number, since it uses less digits than its factorization.

646145 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 129234.

The product of its digits is 2880, while the sum is 26.

The square root of 646145 is about 803.8314499943. The cubic root of 646145 is about 86.4523220607.

The spelling of 646145 in words is "six hundred forty-six thousand, one hundred forty-five".