266261621 has 4 divisors (see below), whose sum is σ = 266479500. Its totient is φ = 266043744.

The previous prime is 266261617. The next prime is 266261629. The reversal of 266261621 is 126162662.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 151536100 + 114725521 = 12310^2 + 10711^2 .

It is a cyclic number.

It is not a de Polignac number, because 266261621 - 2² = 266261617 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 (266261629) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 107096 + ... + 109553.

It is an arithmetic number, because the mean of its divisors is an integer number (66619875).

Almost surely, 2^266261621 is an apocalyptic number.

It is an amenable number.

266261621 is a deficient number, since it is larger than the sum of its proper divisors (217879).

266261621 is a wasteful number, since it uses less digits than its factorization.

266261621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 217878.

The product of its digits is 10368, while the sum is 32.

The square root of 266261621 is about 16317.5249655087. The cubic root of 266261621 is about 643.3335351881. Note that the first 3 decimals are identical.

The spelling of 266261621 in words is "two hundred sixty-six million, two hundred sixty-one thousand, six hundred twenty-one".