981766691 has 4 divisors (see below), whose sum is σ = 1002655392. Its totient is φ = 960877992.

The previous prime is 981766679. The next prime is 981766729. The reversal of 981766691 is 196667189.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 981766691 - 2⁶ = 981766627 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (981786691) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10444280 + ... + 10444373.

It is an arithmetic number, because the mean of its divisors is an integer number (250663848).

Almost surely, 2^981766691 is an apocalyptic number.

981766691 is a deficient number, since it is larger than the sum of its proper divisors (20888701).

981766691 is a wasteful number, since it uses less digits than its factorization.

981766691 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20888700.

The product of its digits is 979776, while the sum is 53.

The square root of 981766691 is about 31333.1564161672. The cubic root of 981766691 is about 993.8849122584.

The spelling of 981766691 in words is "nine hundred eighty-one million, seven hundred sixty-six thousand, six hundred ninety-one".