664251 has 16 divisors (see below), whose sum is σ = 1035264. Its totient is φ = 370944.

The previous prime is 664243. The next prime is 664253. The reversal of 664251 is 152466.

664251 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 664251 - 2³ = 664243 is a prime.

It is an Ulam number.

664251 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (664253) 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, 651 + ... + 1323.

It is an arithmetic number, because the mean of its divisors is an integer number (64704).

2⁶⁶⁴²⁵¹ is an apocalyptic number.

664251 is a deficient number, since it is larger than the sum of its proper divisors (371013).

664251 is a wasteful number, since it uses less digits than its factorization.

664251 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 730.

The product of its digits is 1440, while the sum is 24.

The square root of 664251 is about 815.0159507642. The cubic root of 664251 is about 87.2524048127.

The spelling of 664251 in words is "six hundred sixty-four thousand, two hundred fifty-one".