266789988 has 18 divisors (see below), whose sum is σ = 674385894. Its totient is φ = 88929984.

The previous prime is 266789981. The next prime is 266789989. The reversal of 266789988 is 889987662.

It can be written as a sum of positive squares in only one way, i.e., 245611584 + 21178404 = 15672^2 + 4602^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is not an unprimeable number, because it can be changed into a prime (266789981) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 3705381 + ... + 3705452.

It is an arithmetic number, because the mean of its divisors is an integer number (37465883).

Almost surely, 2^266789988 is an apocalyptic number.

It is an amenable number.

266789988 is an abundant number, since it is smaller than the sum of its proper divisors (407595906).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

266789988 is a wasteful number, since it uses less digits than its factorization.

266789988 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7410843 (or 7410838 counting only the distinct ones).

The product of its digits is 20901888, while the sum is 63.

The square root of 266789988 is about 16333.7071113694. The cubic root of 266789988 is about 643.7587956444.

The spelling of 266789988 in words is "two hundred sixty-six million, seven hundred eighty-nine thousand, nine hundred eighty-eight".