6501266561 has 4 divisors (see below), whose sum is σ = 6501874500. Its totient is φ = 6500658624.

The previous prime is 6501266533. The next prime is 6501266591. The reversal of 6501266561 is 1656621056.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 3107505025 + 3393761536 = 55745^2 + 58256^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-6501266561 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (6501266501) 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, 287636 + ... + 309413.

It is an arithmetic number, because the mean of its divisors is an integer number (1625468625).

Almost surely, 2^6501266561 is an apocalyptic number.

It is an amenable number.

6501266561 is a deficient number, since it is larger than the sum of its proper divisors (607939).

6501266561 is a wasteful number, since it uses less digits than its factorization.

6501266561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 607938.

The product of its (nonzero) digits is 64800, while the sum is 38.

The square root of 6501266561 is about 80630.4319782550. The cubic root of 6501266561 is about 1866.3767872814.

The spelling of 6501266561 in words is "six billion, five hundred one million, two hundred sixty-six thousand, five hundred sixty-one".