6771605661 has 6 divisors (see below), whose sum is σ = 9781208190. Its totient is φ = 4514403768.

The previous prime is 6771605657. The next prime is 6771605663. The reversal of 6771605661 is 1665061776.

6771605661 is a `hidden beast` number, since 6 + 77 + 16 + 0 + 566 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 5371424100 + 1400181561 = 73290^2 + 37419^2 .

It is not a de Polignac number, because 6771605661 - 2² = 6771605657 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6771605663) 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, 376200306 + ... + 376200323.

It is an arithmetic number, because the mean of its divisors is an integer number (1630201365).

Almost surely, 2^6771605661 is an apocalyptic number.

It is an amenable number.

6771605661 is a deficient number, since it is larger than the sum of its proper divisors (3009602529).

6771605661 is a wasteful number, since it uses less digits than its factorization.

6771605661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 752400635 (or 752400632 counting only the distinct ones).

The product of its (nonzero) digits is 317520, while the sum is 45.

The square root of 6771605661 is about 82289.7664415205. The cubic root of 6771605661 is about 1891.8958292741.

The spelling of 6771605661 in words is "six billion, seven hundred seventy-one million, six hundred five thousand, six hundred sixty-one".