1266261866 has 4 divisors (see below), whose sum is σ = 1899392802. Its totient is φ = 633130932.

The previous prime is 1266261833. The next prime is 1266261907. The reversal of 1266261866 is 6681626621.

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

It can be written as a sum of positive squares in only one way, i.e., 1025856841 + 240405025 = 32029^2 + 15505^2 .

It is a super-3 number, since 3×1266261866³ (a number of 28 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 316565465 + ... + 316565468.

Almost surely, 2^1266261866 is an apocalyptic number.

1266261866 is a deficient number, since it is larger than the sum of its proper divisors (633130936).

1266261866 is an equidigital number, since it uses as much as digits as its factorization.

1266261866 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 633130935.

The product of its digits is 248832, while the sum is 44.

The square root of 1266261866 is about 35584.5734272592. The cubic root of 1266261866 is about 1081.8685832991.

The spelling of 1266261866 in words is "one billion, two hundred sixty-six million, two hundred sixty-one thousand, eight hundred sixty-six".