1065666515991 has 32 divisors (see below), whose sum is σ = 1775533056000. Its totient is φ = 552331910880.

The previous prime is 1065666515981. The next prime is 1065666516017. The reversal of 1065666515991 is 1995156665601.

1065666515991 is digitally balanced in base 2 and base 4, because in such bases it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 1065666515991 - 2³³ = 1057076581399 is a prime.

It is a super-2 number, since 2×1065666515991² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1065666515941) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 5152891 + ... + 5355708.

It is an arithmetic number, because the mean of its divisors is an integer number (55485408000).

Almost surely, 2^{1065666515991} is an apocalyptic number.

1065666515991 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1065666515991 is a deficient number, since it is larger than the sum of its proper divisors (709866540009).

1065666515991 is a wasteful number, since it uses less digits than its factorization.

1065666515991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10509059.

The product of its (nonzero) digits is 13122000, while the sum is 60.

The spelling of 1065666515991 in words is "one trillion, sixty-five billion, six hundred sixty-six million, five hundred fifteen thousand, nine hundred ninety-one".