668515 has 16 divisors (see below), whose sum is σ = 875520. Its totient is φ = 488160.

The previous prime is 668513. The next prime is 668527. The reversal of 668515 is 515866.

668515 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 668515 - 2¹ = 668513 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (31).

668515 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (668513) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2832 + ... + 3058.

It is an arithmetic number, because the mean of its divisors is an integer number (54720).

2⁶⁶⁸⁵¹⁵ is an apocalyptic number.

668515 is a deficient number, since it is larger than the sum of its proper divisors (207005).

668515 is a wasteful number, since it uses less digits than its factorization.

668515 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 282.

The product of its digits is 7200, while the sum is 31.

The square root of 668515 is about 817.6276658724. The cubic root of 668515 is about 87.4387053718.

The spelling of 668515 in words is "six hundred sixty-eight thousand, five hundred fifteen".