1171599981 has 8 divisors (see below), whose sum is σ = 1562291424. Its totient is φ = 780987600.

The previous prime is 1171599959. The next prime is 1171599997. The reversal of 1171599981 is 1899951711.

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

It is not a de Polignac number, because 1171599981 - 2⁶ = 1171599917 is a prime.

It is a super-2 number, since 2×1171599981² = 2745293030958400722, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1171599901) 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, 48406 + ... + 68456.

It is an arithmetic number, because the mean of its divisors is an integer number (195286428).

Almost surely, 2^1171599981 is an apocalyptic number.

It is an amenable number.

1171599981 is a deficient number, since it is larger than the sum of its proper divisors (390691443).

1171599981 is a wasteful number, since it uses less digits than its factorization.

1171599981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39531.

The product of its digits is 204120, while the sum is 51.

The square root of 1171599981 is about 34228.6426987691. The cubic root of 1171599981 is about 1054.2083505050.

The spelling of 1171599981 in words is "one billion, one hundred seventy-one million, five hundred ninety-nine thousand, nine hundred eighty-one".