731638 has 8 divisors (see below), whose sum is σ = 1127232. Its totient is φ = 355896.

The previous prime is 731623. The next prime is 731639. The reversal of 731638 is 836137.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (731639) by changing a digit.

731638 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4870 + ... + 5017.

It is an arithmetic number, because the mean of its divisors is an integer number (140904).

2⁷³¹⁶³⁸ is an apocalyptic number.

731638 is a deficient number, since it is larger than the sum of its proper divisors (395594).

731638 is a wasteful number, since it uses less digits than its factorization.

731638 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9926.

The product of its digits is 3024, while the sum is 28.

The square root of 731638 is about 855.3584044130. The cubic root of 731638 is about 90.1084289867.

It can be divided in two parts, 731 and 638, that added together give a square (1369 = 37²).

The spelling of 731638 in words is "seven hundred thirty-one thousand, six hundred thirty-eight".