266605962921 has 45 divisors (see below), whose sum is σ = 402890722311. Its totient is φ = 175695704208.

The previous prime is 266605962863. The next prime is 266605962949. The reversal of 266605962921 is 129269506662.

The square root of 266605962921 is 516339.

It is a perfect power (a square), and thus also a powerful number.

266605962921 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 23395232025 + 243210730896 = 152955^2 + 493164^2 .

It is not a de Polignac number, because 266605962921 - 2⁷ = 266605962793 is a prime.

It is a Smith number, since the sum of its digits (54) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (266605962221) 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 44 ways as a sum of consecutive naturals, for example, 478645975 + ... + 478646531.

Almost surely, 2^266605962921 is an apocalyptic number.

266605962921 is the 516339-th square number.

266605962921 is the 258170-th centered octagonal number.

It is an amenable number.

266605962921 is a deficient number, since it is larger than the sum of its proper divisors (136284759390).

266605962921 is an frugal number, since it uses more digits than its factorization.

266605962921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1332 (or 663 counting only the distinct ones).

The product of its (nonzero) digits is 4199040, while the sum is 54.

The spelling of 266605962921 in words is "two hundred sixty-six billion, six hundred five million, nine hundred sixty-two thousand, nine hundred twenty-one".