7767820500561 has 27 divisors (see below), whose sum is σ = 12333076831803. Its totient is φ = 4707714258720.

The previous prime is 7767820500547. The next prime is 7767820500653. The reversal of 7767820500561 is 1650050287677.

It is a happy number.

The square root of 7767820500561 is 2787081.

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

7767820500561 is a `hidden beast` number, since 7 + 7 + 6 + 7 + 8 + 20 + 50 + 0 + 561 = 666.

It can be written as a sum of positive squares in only one way, i.e., 5019997086225 + 2747823414336 = 2240535^2 + 1657656^2 .

It is not a de Polignac number, because 7767820500561 - 2¹⁵ = 7767820467793 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 7767820500498 and 7767820500507.

It is not an unprimeable number, because it can be changed into a prime (7767820500761) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 91931445 + ... + 92015901.

Almost surely, 2^{7767820500561} is an apocalyptic number.

7767820500561 is the 2787081-st square number.

7767820500561 is the 1393541-st centered octagonal number.

It is an amenable number.

7767820500561 is a deficient number, since it is larger than the sum of its proper divisors (4565256331242).

7767820500561 is an frugal number, since it uses more digits than its factorization.

7767820500561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 168942 (or 84471 counting only the distinct ones).

The product of its (nonzero) digits is 4939200, while the sum is 54.

The spelling of 7767820500561 in words is "seven trillion, seven hundred sixty-seven billion, eight hundred twenty million, five hundred thousand, five hundred sixty-one".