7766720641 has 3 divisors (see below), whose sum is σ = 7766808771. Its totient is φ = 7766632512.

The previous prime is 7766720639. The next prime is 7766720677. The reversal of 7766720641 is 1460276677.

The square root of 7766720641 is 88129.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in only one way, i.e., 1757370241 + 6009350400 = 41921^2 + 77520^2 .

It is not a de Polignac number, because 7766720641 - 2¹ = 7766720639 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 7766720591 and 7766720600.

It is not an unprimeable number, because it can be changed into a prime (7766720341) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 44065 + ... + 132193.

It is an arithmetic number, because the mean of its divisors is an integer number (2588936257).

Almost surely, 2^7766720641 is an apocalyptic number.

7766720641 is the 88129-th square number.

7766720641 is the 44065-th centered octagonal number.

It is an amenable number.

7766720641 is a deficient number, since it is larger than the sum of its proper divisors (88130).

7766720641 is an frugal number, since it uses more digits than its factorization.

7766720641 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 176258 (or 88129 counting only the distinct ones).

The product of its (nonzero) digits is 592704, while the sum is 46.

The cubic root of 7766720641 is about 1980.3679757710.

The spelling of 7766720641 in words is "seven billion, seven hundred sixty-six million, seven hundred twenty thousand, six hundred forty-one".