7656721961 has 16 divisors (see below), whose sum is σ = 9038131200. Its totient is φ = 6347460240.

The previous prime is 7656721939. The next prime is 7656721967. The reversal of 7656721961 is 1691276567.

It is a cyclic number.

It is not a de Polignac number, because 7656721961 - 2¹⁰ = 7656720937 is a prime.

It is not an unprimeable number, because it can be changed into a prime (7656721967) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 395690 + ... + 414588.

It is an arithmetic number, because the mean of its divisors is an integer number (564883200).

Almost surely, 2^7656721961 is an apocalyptic number.

It is an amenable number.

7656721961 is a deficient number, since it is larger than the sum of its proper divisors (1381409239).

7656721961 is a wasteful number, since it uses less digits than its factorization.

7656721961 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20804.

The product of its digits is 952560, while the sum is 50.

The square root of 7656721961 is about 87502.6968784391. The cubic root of 7656721961 is about 1970.9742886166.

The spelling of 7656721961 in words is "seven billion, six hundred fifty-six million, seven hundred twenty-one thousand, nine hundred sixty-one".