1165616661 has 16 divisors (see below), whose sum is σ = 1741267008. Its totient is φ = 687340800.

The previous prime is 1165616653. The next prime is 1165616671. The reversal of 1165616661 is 1666165611.

It is not a de Polignac number, because 1165616661 - 2³ = 1165616653 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1165616671) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 476100 + ... + 478541.

It is an arithmetic number, because the mean of its divisors is an integer number (108829188).

Almost surely, 2^1165616661 is an apocalyptic number.

1165616661 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1165616661 is a deficient number, since it is larger than the sum of its proper divisors (575650347).

1165616661 is a wasteful number, since it uses less digits than its factorization.

1165616661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 954692.

The product of its digits is 38880, while the sum is 39.

The square root of 1165616661 is about 34141.1285841578. The cubic root of 1165616661 is about 1052.4106851313.

The spelling of 1165616661 in words is "one billion, one hundred sixty-five million, six hundred sixteen thousand, six hundred sixty-one".