661011789 has 8 divisors (see below), whose sum is σ = 919668672. Its totient is φ = 421514720.

The previous prime is 661011779. The next prime is 661011797. The reversal of 661011789 is 987110166.

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 661011789 - 2⁴ = 661011773 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661011719) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4789872 + ... + 4790009.

It is an arithmetic number, because the mean of its divisors is an integer number (114958584).

Almost surely, 2^661011789 is an apocalyptic number.

661011789 is a gapful number since it is divisible by the number (69) formed by its first and last digit.

It is an amenable number.

661011789 is a deficient number, since it is larger than the sum of its proper divisors (258656883).

661011789 is a wasteful number, since it uses less digits than its factorization.

661011789 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9579907.

The product of its (nonzero) digits is 18144, while the sum is 39.

The square root of 661011789 is about 25710.1495328207. The cubic root of 661011789 is about 871.1034525480.

The spelling of 661011789 in words is "six hundred sixty-one million, eleven thousand, seven hundred eighty-nine".