731440 has 40 divisors (see below), whose sum is σ = 1749888. Its totient is φ = 284160.

The previous prime is 731413. The next prime is 731447. The reversal of 731440 is 44137.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (40).

It is a hoax number, since the sum of its digits (19) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (731447) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3169 + ... + 3391.

2⁷³¹⁴⁴⁰ 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 731440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (874944).

731440 is an abundant number, since it is smaller than the sum of its proper divisors (1018448).

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

731440 is a wasteful number, since it uses less digits than its factorization.

731440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 277 (or 271 counting only the distinct ones).

The product of its (nonzero) digits is 336, while the sum is 19.

The square root of 731440 is about 855.2426556247. The cubic root of 731440 is about 90.1002997030.

Adding to 731440 its reverse (44137), we get a palindrome (775577).

The spelling of 731440 in words is "seven hundred thirty-one thousand, four hundred forty".