1065888991561 has 3 divisors (see below), whose sum is σ = 1065890023981. Its totient is φ = 1065887959142.

The previous prime is 1065888991547. The next prime is 1065888991579. The reversal of 1065888991561 is 1651998885601.

The square root of 1065888991561 is 1032419.

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 is not a de Polignac number, because 1065888991561 - 2¹⁷ = 1065888860489 is a prime.

It is a super-2 number, since 2×1065888991561² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1065888991061) 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, 516210 + ... + 1548628.

Almost surely, 2^{1065888991561} is an apocalyptic number.

1065888991561 is the 1032419-th square number.

1065888991561 is the 516210-th centered octagonal number.

It is an amenable number.

1065888991561 is a deficient number, since it is larger than the sum of its proper divisors (1032420).

1065888991561 is an frugal number, since it uses more digits than its factorization.

1065888991561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2064838 (or 1032419 counting only the distinct ones).

The product of its (nonzero) digits is 37324800, while the sum is 67.

The spelling of 1065888991561 in words is "one trillion, sixty-five billion, eight hundred eighty-eight million, nine hundred ninety-one thousand, five hundred sixty-one".