266621865 has 32 divisors (see below), whose sum is σ = 448471296. Its totient is φ = 134999040.

The previous prime is 266621843. The next prime is 266621867. The reversal of 266621865 is 568126662.

It is not a de Polignac number, because 266621865 - 2¹⁴ = 266605481 is a prime.

It is not an unprimeable number, because it can be changed into a prime (266621867) 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, 44445 + ... + 50085.

It is an arithmetic number, because the mean of its divisors is an integer number (14014728).

Almost surely, 2^266621865 is an apocalyptic number.

It is an amenable number.

266621865 is a deficient number, since it is larger than the sum of its proper divisors (181849431).

266621865 is a wasteful number, since it uses less digits than its factorization.

266621865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5809.

The product of its digits is 207360, while the sum is 42.

The square root of 266621865 is about 16328.5597956464. The cubic root of 266621865 is about 643.6235414402.

It can be divided in two parts, 2666 and 21865, that added together give a triangular number (24531 = T₂₂₁).

The spelling of 266621865 in words is "two hundred sixty-six million, six hundred twenty-one thousand, eight hundred sixty-five".