766321661 has 16 divisors (see below), whose sum is σ = 934531200. Its totient is φ = 613744128.

The previous prime is 766321657. The next prime is 766321667. The reversal of 766321661 is 166123667.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 766321661 - 2² = 766321657 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (766321667) 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 15 ways as a sum of consecutive naturals, for example, 29756 + ... + 49173.

It is an arithmetic number, because the mean of its divisors is an integer number (58408200).

Almost surely, 2^766321661 is an apocalyptic number.

It is an amenable number.

766321661 is a deficient number, since it is larger than the sum of its proper divisors (168209539).

766321661 is a wasteful number, since it uses less digits than its factorization.

766321661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 79028.

The product of its digits is 54432, while the sum is 38.

The square root of 766321661 is about 27682.5154384496. The cubic root of 766321661 is about 915.1038177363.

The spelling of 766321661 in words is "seven hundred sixty-six million, three hundred twenty-one thousand, six hundred sixty-one".