213236640 has 144 divisors (see below), whose sum is σ = 731458728. Its totient is φ = 56567808.

The previous prime is 213236633. The next prime is 213236641. The reversal of 213236640 is 46632312.

213236640 is a `hidden beast` number, since 2 + 13 + 2 + 3 + 6 + 640 = 666.

213236640 is digitally balanced in base 3, 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 4 ways, for example, as 187470864 + 25765776 = 13692^2 + 5076^2 .

It is a tau number, because it is divible by the number of its divisors (144).

It is not an unprimeable number, because it can be changed into a prime (213236641) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 536922 + ... + 537318.

Almost surely, 2^213236640 is an apocalyptic number.

213236640 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 213236640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (365729364).

213236640 is an abundant number, since it is smaller than the sum of its proper divisors (518222088).

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

213236640 is a wasteful number, since it uses less digits than its factorization.

213236640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 791 (or 780 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 27.

The square root of 213236640 is about 14602.6244216579. The cubic root of 213236640 is about 597.4303438228.

Adding to 213236640 its reverse (46632312), we get a palindrome (259868952).

The spelling of 213236640 in words is "two hundred thirteen million, two hundred thirty-six thousand, six hundred forty".