661244513 has 4 divisors (see below), whose sum is σ = 670557888. Its totient is φ = 651931140.

The previous prime is 661244509. The next prime is 661244531. The reversal of 661244513 is 315442166.

661244513 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 661244513 - 2² = 661244509 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 661244513.

It is not an unprimeable number, because it can be changed into a prime (661244533) 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, 4656581 + ... + 4656722.

It is an arithmetic number, because the mean of its divisors is an integer number (167639472).

Almost surely, 2^661244513 is an apocalyptic number.

It is an amenable number.

661244513 is a deficient number, since it is larger than the sum of its proper divisors (9313375).

661244513 is an equidigital number, since it uses as much as digits as its factorization.

661244513 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9313374.

The product of its digits is 17280, while the sum is 32.

The square root of 661244513 is about 25714.6750514176. The cubic root of 661244513 is about 871.2056710442.

Adding to 661244513 its reverse (315442166), we get a palindrome (976686679).

The spelling of 661244513 in words is "six hundred sixty-one million, two hundred forty-four thousand, five hundred thirteen".