1660000991 has 8 divisors (see below), whose sum is σ = 1840597968. Its totient is φ = 1484352000.

The previous prime is 1660000963. The next prime is 1660001017. The reversal of 1660000991 is 1990000661.

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 1660000991 - 2¹⁰ = 1659999967 is a prime.

1660000991 is a strobogrammatic number because it is the same when read upside-down.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1660000961) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1236290 + ... + 1237631.

It is an arithmetic number, because the mean of its divisors is an integer number (230074746).

Almost surely, 2^1660000991 is an apocalyptic number.

1660000991 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1660000991 is a deficient number, since it is larger than the sum of its proper divisors (180596977).

1660000991 is a wasteful number, since it uses less digits than its factorization.

1660000991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2473993.

The product of its (nonzero) digits is 2916, while the sum is 32.

The square root of 1660000991 is about 40743.1097364941. The cubic root of 1660000991 is about 1184.0483831637.

The spelling of 1660000991 in words is "one billion, six hundred sixty million, nine hundred ninety-one", and thus it is an aban number.