7781216989 has 16 divisors (see below), whose sum is σ = 9719828608. Its totient is φ = 6064673472.

The previous prime is 7781216977. The next prime is 7781217011. The reversal of 7781216989 is 9896121877.

It is not a de Polignac number, because 7781216989 - 2⁹ = 7781216477 is a prime.

It is a super-2 number, since 2×7781216989² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7781216959) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 632022 + ... + 644215.

It is an arithmetic number, because the mean of its divisors is an integer number (607489288).

Almost surely, 2^7781216989 is an apocalyptic number.

It is an amenable number.

7781216989 is a deficient number, since it is larger than the sum of its proper divisors (1938611619).

7781216989 is a wasteful number, since it uses less digits than its factorization.

7781216989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1276324.

The product of its digits is 3048192, while the sum is 58.

The square root of 7781216989 is about 88211.2067086717. The cubic root of 7781216989 is about 1981.5993088837.

The spelling of 7781216989 in words is "seven billion, seven hundred eighty-one million, two hundred sixteen thousand, nine hundred eighty-nine".