638456 has 32 divisors (see below), whose sum is σ = 1475040. Its totient is φ = 252288.

The previous prime is 638453. The next prime is 638459. The reversal of 638456 is 654836.

638456 = 299² + 300² + ... + 305².

It is an interprime number because it is at equal distance from previous prime (638453) and next prime (638459).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638453) 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 7 ways as a sum of consecutive naturals, for example, 290 + ... + 1166.

It is an arithmetic number, because the mean of its divisors is an integer number (46095).

2⁶³⁸⁴⁵⁶ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 638456, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (737520).

638456 is an abundant number, since it is smaller than the sum of its proper divisors (836584).

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

638456 is a wasteful number, since it uses less digits than its factorization.

638456 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 903 (or 899 counting only the distinct ones).

The product of its digits is 17280, while the sum is 32.

The square root of 638456 is about 799.0344172813. The cubic root of 638456 is about 86.1080308144.

The spelling of 638456 in words is "six hundred thirty-eight thousand, four hundred fifty-six".