1266556566 has 32 divisors (see below), whose sum is σ = 2767540608. Its totient is φ = 383229440.

The previous prime is 1266556547. The next prime is 1266556567. The reversal of 1266556566 is 6656556621.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1266556567) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 31030 + ... + 59126.

It is an arithmetic number, because the mean of its divisors is an integer number (86485644).

Almost surely, 2^1266556566 is an apocalyptic number.

1266556566 is an abundant number, since it is smaller than the sum of its proper divisors (1500984042).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1266556566 is a wasteful number, since it uses less digits than its factorization.

1266556566 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28796.

The product of its digits is 1944000, while the sum is 48.

The square root of 1266556566 is about 35588.7140256571. The cubic root of 1266556566 is about 1081.9525053665.

The spelling of 1266556566 in words is "one billion, two hundred sixty-six million, five hundred fifty-six thousand, five hundred sixty-six".