645146 has 4 divisors (see below), whose sum is σ = 967722. Its totient is φ = 322572.

The previous prime is 645137. The next prime is 645149. The reversal of 645146 is 641546.

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 only one way, i.e., 600625 + 44521 = 775^2 + 211^2 .

It is a super-2 number, since 2×645146² = 832426722632, which contains 22 as substring.

It is a Curzon number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 645146.

It is not an unprimeable number, because it can be changed into a prime (645149) by changing a digit.

645146 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 161285 + ... + 161288.

2⁶⁴⁵¹⁴⁶ is an apocalyptic number.

645146 is a deficient number, since it is larger than the sum of its proper divisors (322576).

645146 is a wasteful number, since it uses less digits than its factorization.

645146 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 322575.

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

The square root of 645146 is about 803.2098106971. The cubic root of 645146 is about 86.4077446476.

Subtracting from 645146 its reverse (641546), we obtain a square (3600 = 60²).

The spelling of 645146 in words is "six hundred forty-five thousand, one hundred forty-six".