766782186921 has 9 divisors (see below), whose sum is σ = 1107578064541. Its totient is φ = 511186373292.

The previous prime is 766782186899. The next prime is 766782186977. The reversal of 766782186921 is 129681287667.

The square root of 766782186921 is 875661.

It is a perfect power (a square), and thus also a powerful number.

It is a tau number, because it is divible by the number of its divisors (9).

It is a de Polignac number, because none of the positive numbers 2^k-766782186921 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (766782185921) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 2481040 + ... + 2772926.

Almost surely, 2^766782186921 is an apocalyptic number.

766782186921 is the 875661-st square number.

766782186921 is the 437831-st centered octagonal number.

It is an amenable number.

766782186921 is a deficient number, since it is larger than the sum of its proper divisors (340795877620).

766782186921 is an frugal number, since it uses more digits than its factorization.

766782186921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 583780 (or 291890 counting only the distinct ones).

The product of its digits is 24385536, while the sum is 63.

The spelling of 766782186921 in words is "seven hundred sixty-six billion, seven hundred eighty-two million, one hundred eighty-six thousand, nine hundred twenty-one".