1165661989 has 8 divisors (see below), whose sum is σ = 1269324000. Its totient is φ = 1066231152.

The previous prime is 1165661977. The next prime is 1165662067. The reversal of 1165661989 is 9891665611.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1165661989 - 2⁵ = 1165661957 is a prime.

It is a super-2 number, since 2×1165661989² = 2717535745198872242, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1165661909) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1057219 + ... + 1058320.

It is an arithmetic number, because the mean of its divisors is an integer number (158665500).

Almost surely, 2^1165661989 is an apocalyptic number.

1165661989 is a gapful number since it is divisible by the number (19) formed by its first and last digit.

It is an amenable number.

1165661989 is a deficient number, since it is larger than the sum of its proper divisors (103662011).

1165661989 is a wasteful number, since it uses less digits than its factorization.

1165661989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2115587.

The product of its digits is 699840, while the sum is 52.

The square root of 1165661989 is about 34141.7924104755. The cubic root of 1165661989 is about 1052.4243268527.

The spelling of 1165661989 in words is "one billion, one hundred sixty-five million, six hundred sixty-one thousand, nine hundred eighty-nine".