7791561 has 6 divisors (see below), whose sum is σ = 11254490. Its totient is φ = 5194368.

The previous prime is 7791551. The next prime is 7791569. The reversal of 7791561 is 1651977.

7791561 is a `hidden beast` number, since 7 + 7 + 91 + 561 = 666.

7791561 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 7733961 + 57600 = 2781^2 + 240^2 .

It is not a de Polignac number, because 7791561 - 2⁵ = 7791529 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (7791569) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 432856 + ... + 432873.

Almost surely, 2^7791561 is an apocalyptic number.

It is an amenable number.

7791561 is a deficient number, since it is larger than the sum of its proper divisors (3462929).

7791561 is a wasteful number, since it uses less digits than its factorization.

7791561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 865735 (or 865732 counting only the distinct ones).

The product of its digits is 13230, while the sum is 36.

The square root of 7791561 is about 2791.3367765284. The cubic root of 7791561 is about 198.2477004017.

The spelling of 7791561 in words is "seven million, seven hundred ninety-one thousand, five hundred sixty-one".