615440 has 60 divisors (see below), whose sum is σ = 1675116. Its totient is φ = 209664.

The previous prime is 615437. The next prime is 615449. The reversal of 615440 is 44516.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 200704 + 414736 = 448^2 + 644^2 .

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a nialpdrome in base 16.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 615440.

It is not an unprimeable number, because it can be changed into a prime (615449) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3842 + ... + 3998.

2⁶¹⁵⁴⁴⁰ is an apocalyptic number.

It is a pronic number, being equal to 784×785.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 615440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (837558).

615440 is an abundant number, since it is smaller than the sum of its proper divisors (1059676).

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

615440 is a wasteful number, since it uses less digits than its factorization.

615440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 184 (or 171 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 20.

The square root of 615440 is about 784.4998406628. The cubic root of 615440 is about 85.0606257223.

Adding to 615440 its reverse (44516), we get a palindrome (659956).

The spelling of 615440 in words is "six hundred fifteen thousand, four hundred forty".