2660599561 has 3 divisors (see below), whose sum is σ = 2660651143. Its totient is φ = 2660547980.

The previous prime is 2660599549. The next prime is 2660599567. The reversal of 2660599561 is 1659950662.

The square root of 2660599561 is 51581.

It is a perfect power (a square), and thus also a powerful number.

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 only one way, i.e., 12467961 + 2648131600 = 3531^2 + 51460^2 .

It is a de Polignac number, because none of the positive numbers 2^k-2660599561 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2660599567) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 25791 + ... + 77371.

Almost surely, 2^2660599561 is an apocalyptic number.

2660599561 is the 51581-st square number.

2660599561 is the 25791-st centered octagonal number.

It is an amenable number.

2660599561 is a deficient number, since it is larger than the sum of its proper divisors (51582).

2660599561 is an frugal number, since it uses more digits than its factorization.

2660599561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 103162 (or 51581 counting only the distinct ones).

The product of its (nonzero) digits is 874800, while the sum is 49.

The cubic root of 2660599561 is about 1385.6700760853.

Multiplying 2660599561 by its sum of digits (49), we get a square (130369378489 = 361067²).

The spelling of 2660599561 in words is "two billion, six hundred sixty million, five hundred ninety-nine thousand, five hundred sixty-one".