615649 has 4 divisors (see below), whose sum is σ = 617220. Its totient is φ = 614080.

The previous prime is 615623. The next prime is 615661. The reversal of 615649 is 946516.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 216225 + 399424 = 465^2 + 632^2 .

It is a cyclic number.

It is not a de Polignac number, because 615649 - 2⁵ = 615617 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 615649.

It is not an unprimeable number, because it can be changed into a prime (615679) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 357 + ... + 1165.

It is an arithmetic number, because the mean of its divisors is an integer number (154305).

2⁶¹⁵⁶⁴⁹ is an apocalyptic number.

It is an amenable number.

615649 is a deficient number, since it is larger than the sum of its proper divisors (1571).

615649 is an equidigital number, since it uses as much as digits as its factorization.

615649 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1570.

The product of its digits is 6480, while the sum is 31.

The square root of 615649 is about 784.6330352464. The cubic root of 615649 is about 85.0702533376.

The spelling of 615649 in words is "six hundred fifteen thousand, six hundred forty-nine".