645620 has 24 divisors (see below), whose sum is σ = 1428000. Its totient is φ = 244512.

The previous prime is 645611. The next prime is 645629. The reversal of 645620 is 26546.

It is an interprime number because it is at equal distance from previous prime (645611) and next prime (645629).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645629) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 470 + ... + 1229.

It is an arithmetic number, because the mean of its divisors is an integer number (59500).

2⁶⁴⁵⁶²⁰ is an apocalyptic number.

It is an amenable number.

645620 is an abundant number, since it is smaller than the sum of its proper divisors (782380).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

645620 is a wasteful number, since it uses less digits than its factorization.

645620 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1727 (or 1725 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 23.

The square root of 645620 is about 803.5048226364. The cubic root of 645620 is about 86.4289012252.

The spelling of 645620 in words is "six hundred forty-five thousand, six hundred twenty".