6909561 has 6 divisors (see below), whose sum is σ = 9980490. Its totient is φ = 4606368.

The previous prime is 6909547. The next prime is 6909563. The reversal of 6909561 is 1659096.

6909561 is a `hidden beast` number, since 6 + 90 + 9 + 561 = 666.

It can be written as a sum of positive squares in only one way, i.e., 4410000 + 2499561 = 2100^2 + 1581^2 .

It is not a de Polignac number, because 6909561 - 2¹⁰ = 6908537 is a prime.

6909561 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (6909563) 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, 383856 + ... + 383873.

It is an arithmetic number, because the mean of its divisors is an integer number (1663415).

Almost surely, 2^6909561 is an apocalyptic number.

It is an amenable number.

6909561 is a deficient number, since it is larger than the sum of its proper divisors (3070929).

6909561 is a wasteful number, since it uses less digits than its factorization.

6909561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 767735 (or 767732 counting only the distinct ones).

The product of its (nonzero) digits is 14580, while the sum is 36.

The square root of 6909561 is about 2628.6043825574. The cubic root of 6909561 is about 190.4657180959.

The spelling of 6909561 in words is "six million, nine hundred nine thousand, five hundred sixty-one".