1266721863 has 32 divisors (see below), whose sum is σ = 1908375552. Its totient is φ = 740728800.

The previous prime is 1266721853. The next prime is 1266721891. The reversal of 1266721863 is 3681276621.

It is not a de Polignac number, because 1266721863 - 2⁸ = 1266721607 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1266721843) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 104370 + ... + 115872.

It is an arithmetic number, because the mean of its divisors is an integer number (59636736).

Almost surely, 2^1266721863 is an apocalyptic number.

1266721863 is a deficient number, since it is larger than the sum of its proper divisors (641653689).

1266721863 is a wasteful number, since it uses less digits than its factorization.

1266721863 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11635.

The product of its digits is 145152, while the sum is 42.

The square root of 1266721863 is about 35591.0362731967. The cubic root of 1266721863 is about 1081.9995714901. Note that the first 3 decimals are identical.

The spelling of 1266721863 in words is "one billion, two hundred sixty-six million, seven hundred twenty-one thousand, eight hundred sixty-three".