1266720705 has 24 divisors (see below), whose sum is σ = 2208354408. Its totient is φ = 671675136.

The previous prime is 1266720691. The next prime is 1266720757. The reversal of 1266720705 is 5070276621.

It can be written as a sum of positive squares in 4 ways, for example, as 233998209 + 1032722496 = 15297^2 + 32136^2 .

It is not a de Polignac number, because 1266720705 - 2²⁶ = 1199611841 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1266720705.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 73572 + ... + 89141.

It is an arithmetic number, because the mean of its divisors is an integer number (92014767).

Almost surely, 2^1266720705 is an apocalyptic number.

1266720705 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1266720705 is a deficient number, since it is larger than the sum of its proper divisors (941633703).

1266720705 is a wasteful number, since it uses less digits than its factorization.

1266720705 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 162897 (or 162894 counting only the distinct ones).

The product of its (nonzero) digits is 35280, while the sum is 36.

The square root of 1266720705 is about 35591.0200050518. The cubic root of 1266720705 is about 1081.9992417792. Note that the first 3 decimals are identical.

The spelling of 1266720705 in words is "one billion, two hundred sixty-six million, seven hundred twenty thousand, seven hundred five".