645533 has 4 divisors (see below), whose sum is σ = 737760. Its totient is φ = 553308.

The previous prime is 645529. The next prime is 645571. The reversal of 645533 is 335546.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 645533 - 2² = 645529 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645503) 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, 46103 + ... + 46116.

It is an arithmetic number, because the mean of its divisors is an integer number (184440).

2⁶⁴⁵⁵³³ is an apocalyptic number.

It is an amenable number.

645533 is a deficient number, since it is larger than the sum of its proper divisors (92227).

645533 is an equidigital number, since it uses as much as digits as its factorization.

645533 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 92226.

The product of its digits is 5400, while the sum is 26.

The square root of 645533 is about 803.4506829918. The cubic root of 645533 is about 86.4250188320.

The spelling of 645533 in words is "six hundred forty-five thousand, five hundred thirty-three".