1266540566 has 4 divisors (see below), whose sum is σ = 1899810852. Its totient is φ = 633270282.

The previous prime is 1266540559. The next prime is 1266540593. The reversal of 1266540566 is 6650456621.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 316635140 + ... + 316635143.

It is an arithmetic number, because the mean of its divisors is an integer number (474952713).

Almost surely, 2^1266540566 is an apocalyptic number.

1266540566 is a deficient number, since it is larger than the sum of its proper divisors (633270286).

1266540566 is an equidigital number, since it uses as much as digits as its factorization.

1266540566 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 633270285.

The product of its (nonzero) digits is 259200, while the sum is 41.

The square root of 1266540566 is about 35588.4892345826. The cubic root of 1266540566 is about 1081.9479493618.

The spelling of 1266540566 in words is "one billion, two hundred sixty-six million, five hundred forty thousand, five hundred sixty-six".