639553 has 4 divisors (see below), whose sum is σ = 648388. Its totient is φ = 630720.

The previous prime is 639547. The next prime is 639563. The reversal of 639553 is 355936.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 186624 + 452929 = 432^2 + 673^2 .

It is not a de Polignac number, because 639553 - 2¹³ = 631361 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (639533) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4308 + ... + 4453.

It is an arithmetic number, because the mean of its divisors is an integer number (162097).

2⁶³⁹⁵⁵³ is an apocalyptic number.

It is an amenable number.

639553 is a deficient number, since it is larger than the sum of its proper divisors (8835).

639553 is an equidigital number, since it uses as much as digits as its factorization.

639553 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8834.

The product of its digits is 12150, while the sum is 31.

The square root of 639553 is about 799.7205762015. The cubic root of 639553 is about 86.1573197555.

The spelling of 639553 in words is "six hundred thirty-nine thousand, five hundred fifty-three".