7720776217 has 64 divisors (see below), whose sum is σ = 10351411200. Its totient is φ = 5577768000.

The previous prime is 7720776211. The next prime is 7720776241. The reversal of 7720776217 is 7126770277.

It is not a de Polignac number, because 7720776217 - 2¹⁵ = 7720743449 is a prime.

It is a super-2 number, since 2×7720776217² (a number of 21 digits) contains 22 as substring.

It is a Smith number, since the sum of its digits (46) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (7720776211) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 24825492 + ... + 24825802.

It is an arithmetic number, because the mean of its divisors is an integer number (161740800).

Almost surely, 2^7720776217 is an apocalyptic number.

7720776217 is a gapful number since it is divisible by the number (77) formed by its first and last digit.

It is an amenable number.

7720776217 is a deficient number, since it is larger than the sum of its proper divisors (2630634983).

7720776217 is a wasteful number, since it uses less digits than its factorization.

7720776217 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 658.

The product of its (nonzero) digits is 403368, while the sum is 46.

The square root of 7720776217 is about 87867.9476088978. The cubic root of 7720776217 is about 1976.4552617449.

The spelling of 7720776217 in words is "seven billion, seven hundred twenty million, seven hundred seventy-six thousand, two hundred seventeen".