6621646651 has 16 divisors (see below), whose sum is σ = 6866703360. Its totient is φ = 6380281440.

The previous prime is 6621646643. The next prime is 6621646711. The reversal of 6621646651 is 1566461266.

It is a cyclic number.

It is not a de Polignac number, because 6621646651 - 2³ = 6621646643 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 6621646598 and 6621646607.

It is not an unprimeable number, because it can be changed into a prime (6621646621) 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 15 ways as a sum of consecutive naturals, for example, 2999190 + ... + 3001396.

It is an arithmetic number, because the mean of its divisors is an integer number (429168960).

Almost surely, 2^6621646651 is an apocalyptic number.

6621646651 is a deficient number, since it is larger than the sum of its proper divisors (245056709).

6621646651 is a wasteful number, since it uses less digits than its factorization.

6621646651 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2994.

The product of its digits is 311040, while the sum is 43.

The square root of 6621646651 is about 81373.5009139953. The cubic root of 6621646651 is about 1877.8259396786.

The spelling of 6621646651 in words is "six billion, six hundred twenty-one million, six hundred forty-six thousand, six hundred fifty-one".