1165661988 has 24 divisors (see below), whose sum is σ = 2838134208. Its totient is φ = 371660256.

The previous prime is 1165661977. The next prime is 1165662067. The reversal of 1165661988 is 8891665611.

It is a super-2 number, since 2×1165661988² = 2717535740536224288, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 1165661988.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2111431 + ... + 2111982.

It is an arithmetic number, because the mean of its divisors is an integer number (118255592).

Almost surely, 2^1165661988 is an apocalyptic number.

It is an amenable number.

1165661988 is an abundant number, since it is smaller than the sum of its proper divisors (1672472220).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1165661988 is a wasteful number, since it uses less digits than its factorization.

1165661988 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4223443 (or 4223441 counting only the distinct ones).

The product of its digits is 622080, while the sum is 51.

The square root of 1165661988 is about 34141.7923958307. The cubic root of 1165661988 is about 1052.4243265517.

The spelling of 1165661988 in words is "one billion, one hundred sixty-five million, six hundred sixty-one thousand, nine hundred eighty-eight".