2643913561 has 3 divisors (see below), whose sum is σ = 2643964981. Its totient is φ = 2643862142.

The previous prime is 2643913541. The next prime is 2643913583. The reversal of 2643913561 is 1653193462.

The square root of 2643913561 is 51419.

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, and also an emirpimes, since its reverse is a distinct semiprime: 1653193462 = 2 ⋅826596731.

It is a de Polignac number, because none of the positive numbers 2^k-2643913561 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2643913541) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 25710 + ... + 77128.

Almost surely, 2^2643913561 is an apocalyptic number.

2643913561 is the 51419-th square number.

2643913561 is the 25710-th centered octagonal number.

It is an amenable number.

2643913561 is a deficient number, since it is larger than the sum of its proper divisors (51420).

2643913561 is an frugal number, since it uses more digits than its factorization.

2643913561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 102838 (or 51419 counting only the distinct ones).

The product of its digits is 116640, while the sum is 40.

The cubic root of 2643913561 is about 1382.7672472708.

It can be divided in two parts, 26439 and 13561, that added together give a square (40000 = 200²).

The spelling of 2643913561 in words is "two billion, six hundred forty-three million, nine hundred thirteen thousand, five hundred sixty-one".