6645512061 has 12 divisors (see below), whose sum is σ = 10016424288. Its totient is φ = 4237717704.

The previous prime is 6645512057. The next prime is 6645512077. The reversal of 6645512061 is 1602155466.

6645512061 is a `hidden beast` number, since 6 + 645 + 5 + 1 + 2 + 0 + 6 + 1 = 666.

It is not a de Polignac number, because 6645512061 - 2² = 6645512057 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6645512051) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 16051755 + ... + 16052168.

It is an arithmetic number, because the mean of its divisors is an integer number (834702024).

Almost surely, 2^6645512061 is an apocalyptic number.

It is an amenable number.

6645512061 is a deficient number, since it is larger than the sum of its proper divisors (3370912227).

6645512061 is a wasteful number, since it uses less digits than its factorization.

6645512061 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32103952 (or 32103949 counting only the distinct ones).

The product of its (nonzero) digits is 43200, while the sum is 36.

The square root of 6645512061 is about 81520.0101876834. The cubic root of 6645512061 is about 1880.0792237816.

The spelling of 6645512061 in words is "six billion, six hundred forty-five million, five hundred twelve thousand, sixty-one".