6661640525 has 12 divisors (see below), whose sum is σ = 8273544864. Its totient is φ = 5320854000.

The previous prime is 6661640501. The next prime is 6661640567. The reversal of 6661640525 is 5250461666.

It is a de Polignac number, because none of the positive numbers 2^k-6661640525 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 195371 + ... + 226920.

It is an arithmetic number, because the mean of its divisors is an integer number (689462072).

Almost surely, 2^6661640525 is an apocalyptic number.

It is an amenable number.

6661640525 is a deficient number, since it is larger than the sum of its proper divisors (1611904339).

6661640525 is a wasteful number, since it uses less digits than its factorization.

6661640525 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 422932 (or 422927 counting only the distinct ones).

The product of its (nonzero) digits is 259200, while the sum is 41.

The square root of 6661640525 is about 81618.8735832589. The cubic root of 6661640525 is about 1881.5989608101.

The spelling of 6661640525 in words is "six billion, six hundred sixty-one million, six hundred forty thousand, five hundred twenty-five".