1660880991 has 64 divisors (see below), whose sum is σ = 3032801280. Its totient is φ = 781799040.

The previous prime is 1660880989. The next prime is 1660881043. The reversal of 1660880991 is 1990880661.

It is not a de Polignac number, because 1660880991 - 2¹ = 1660880989 is a prime.

1660880991 is a strobogrammatic number because it is the same when read upside-down.

It is a self number, because there is not a number n which added to its sum of digits gives 1660880991.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1660880951) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 92721 + ... + 109173.

It is an arithmetic number, because the mean of its divisors is an integer number (47387520).

Almost surely, 2^1660880991 is an apocalyptic number.

1660880991 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1660880991 is a deficient number, since it is larger than the sum of its proper divisors (1371920289).

1660880991 is a wasteful number, since it uses less digits than its factorization.

1660880991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16516.

The product of its (nonzero) digits is 186624, while the sum is 48.

The square root of 1660880991 is about 40753.9076776694. The cubic root of 1660880991 is about 1184.2575755106.

The spelling of 1660880991 in words is "one billion, six hundred sixty million, eight hundred eighty thousand, nine hundred ninety-one".