266409821 has 16 divisors (see below), whose sum is σ = 276369408. Its totient is φ = 256704000.

The previous prime is 266409797. The next prime is 266409823. The reversal of 266409821 is 128904662.

It is a cyclic number.

It is not a de Polignac number, because 266409821 - 2¹⁰ = 266408797 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (266409823) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 695396 + ... + 695778.

It is an arithmetic number, because the mean of its divisors is an integer number (17273088).

Almost surely, 2^266409821 is an apocalyptic number.

It is an amenable number.

266409821 is a deficient number, since it is larger than the sum of its proper divisors (9959587).

266409821 is a wasteful number, since it uses less digits than its factorization.

266409821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 652.

The product of its (nonzero) digits is 41472, while the sum is 38.

The square root of 266409821 is about 16322.0654636599. The cubic root of 266409821 is about 643.4528718841.

The spelling of 266409821 in words is "two hundred sixty-six million, four hundred nine thousand, eight hundred twenty-one".