645015 has 16 divisors (see below), whose sum is σ = 1179648. Its totient is φ = 294816.

The previous prime is 645013. The next prime is 645019. The reversal of 645015 is 510546.

It is a happy number.

It is not a de Polignac number, because 645015 - 2¹ = 645013 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a junction number, because it is equal to n+sod(n) for n = 644982 and 645000.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (645011) by changing a digit.

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 in 15 ways as a sum of consecutive naturals, for example, 2967 + ... + 3176.

It is an arithmetic number, because the mean of its divisors is an integer number (73728).

2⁶⁴⁵⁰¹⁵ is an apocalyptic number.

645015 is a deficient number, since it is larger than the sum of its proper divisors (534633).

645015 is a wasteful number, since it uses less digits than its factorization.

645015 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6158.

The product of its (nonzero) digits is 600, while the sum is 21.

The square root of 645015 is about 803.1282587483. The cubic root of 645015 is about 86.4018957489.

The spelling of 645015 in words is "six hundred forty-five thousand, fifteen".