766866252681 has 15 divisors (see below), whose sum is σ = 1145577410263. Its totient is φ = 511238914200.

The previous prime is 766866252679. The next prime is 766866252697. The reversal of 766866252681 is 186252668667.

It is a happy number.

The square root of 766866252681 is 875709.

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

It can be written as a sum of positive squares in only one way, i.e., 1906108281 + 764960144400 = 43659^2 + 874620^2 .

It is not a de Polignac number, because 766866252681 - 2¹ = 766866252679 is a prime.

It is a super-2 number, since 2×766866252681² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (766866252601) by changing a digit.

It is a polite number, since it can be written in 14 ways as a sum of consecutive naturals, for example, 7832731 + ... + 7930031.

Almost surely, 2^766866252681 is an apocalyptic number.

766866252681 is the 875709-th square number.

766866252681 is the 437855-th centered octagonal number.

It is an amenable number.

766866252681 is a deficient number, since it is larger than the sum of its proper divisors (378711157582).

766866252681 is an frugal number, since it uses more digits than its factorization.

766866252681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 194614 (or 97304 counting only the distinct ones).

The product of its digits is 69672960, while the sum is 63.

The spelling of 766866252681 in words is "seven hundred sixty-six billion, eight hundred sixty-six million, two hundred fifty-two thousand, six hundred eighty-one".