1266921 has 10 divisors (see below), whose sum is σ = 1892682. Its totient is φ = 844560.

The previous prime is 1266919. The next prime is 1266929. The reversal of 1266921 is 1296621.

It can be written as a sum of positive squares in only one way, i.e., 1265625 + 1296 = 1125^2 + 36^2 .

It is not a de Polignac number, because 1266921 - 2¹ = 1266919 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (1266929) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 7740 + ... + 7901.

2^1266921 is an apocalyptic number.

It is an amenable number.

1266921 is a deficient number, since it is larger than the sum of its proper divisors (625761).

1266921 is an equidigital number, since it uses as much as digits as its factorization.

1266921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15653 (or 15644 counting only the distinct ones).

The product of its digits is 1296, while the sum is 27.

The square root of 1266921 is about 1125.5758526194. The cubic root of 1266921 is about 108.2056267667.

Subtracting from 1266921 its product of digits (1296), we obtain a square (1265625 = 1125²).

It can be divided in two parts, 1266 and 921, that added together give a 7-th power (2187 = 3⁷).

The spelling of 1266921 in words is "one million, two hundred sixty-six thousand, nine hundred twenty-one".