266042640 has 80 divisors (see below), whose sum is σ = 827857728. Its totient is φ = 70675968.

The previous prime is 266042599. The next prime is 266042641. The reversal of 266042640 is 46240662.

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 266042598 and 266042607.

It is not an unprimeable number, because it can be changed into a prime (266042641) 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, 65962 + ... + 69878.

Almost surely, 2^266042640 is an apocalyptic number.

266042640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 266042640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (413928864).

266042640 is an abundant number, since it is smaller than the sum of its proper divisors (561815088).

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

266042640 is a wasteful number, since it uses less digits than its factorization.

266042640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4216 (or 4210 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 30.

The square root of 266042640 is about 16310.8135909893. The cubic root of 266042640 is about 643.1571216559.

The spelling of 266042640 in words is "two hundred sixty-six million, forty-two thousand, six hundred forty".