645046 has 4 divisors (see below), whose sum is σ = 967572. Its totient is φ = 322522.

The previous prime is 645041. The next prime is 645049. The reversal of 645046 is 640546.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 640546 = 2 ⋅320273.

It is a self number, because there is not a number n which added to its sum of digits gives 645046.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645041) by changing a digit.

645046 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 161260 + ... + 161263.

It is an arithmetic number, because the mean of its divisors is an integer number (241893).

2⁶⁴⁵⁰⁴⁶ is an apocalyptic number.

645046 is a deficient number, since it is larger than the sum of its proper divisors (322526).

645046 is a wasteful number, since it uses less digits than its factorization.

645046 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 322525.

The product of its (nonzero) digits is 2880, while the sum is 25.

The square root of 645046 is about 803.1475580490. The cubic root of 645046 is about 86.4032799109.

The spelling of 645046 in words is "six hundred forty-five thousand, forty-six".