638694 has 48 divisors (see below), whose sum is σ = 1636128. Its totient is φ = 176256.

The previous prime is 638689. The next prime is 638699. The reversal of 638694 is 496836.

638694 = T₁₆₇ + T₁₆₈ + ... + T₂₀₃.

It is an interprime number because it is at equal distance from previous prime (638689) and next prime (638699).

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 638694.

It is not an unprimeable number, because it can be changed into a prime (638699) by changing a digit.

638694 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

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 23 ways as a sum of consecutive naturals, for example, 4594 + ... + 4730.

It is an arithmetic number, because the mean of its divisors is an integer number (34086).

2⁶³⁸⁶⁹⁴ is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 638694, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (818064).

638694 is an abundant number, since it is smaller than the sum of its proper divisors (997434).

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

638694 is a wasteful number, since it uses less digits than its factorization.

638694 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 189 (or 186 counting only the distinct ones).

The product of its digits is 31104, while the sum is 36.

The square root of 638694 is about 799.1833331595. The cubic root of 638694 is about 86.1187291060.

The spelling of 638694 in words is "six hundred thirty-eight thousand, six hundred ninety-four".