21255240333 has 16 divisors (see below), whose sum is σ = 28851109056. Its totient is φ = 13916997120.

The previous prime is 21255240329. The next prime is 21255240341. The reversal of 21255240333 is 33304255212.

It is not a de Polignac number, because 21255240333 - 2² = 21255240329 is a prime.

It is a super-2 number, since 2×21255240333² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21255240333.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21255240133) 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 15 ways as a sum of consecutive naturals, for example, 240666 + ... + 316907.

It is an arithmetic number, because the mean of its divisors is an integer number (1803194316).

Almost surely, 2^21255240333 is an apocalyptic number.

It is an amenable number.

21255240333 is a deficient number, since it is larger than the sum of its proper divisors (7595868723).

21255240333 is a wasteful number, since it uses less digits than its factorization.

21255240333 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 557804.

The product of its (nonzero) digits is 21600, while the sum is 30.

Adding to 21255240333 its reverse (33304255212), we get a palindrome (54559495545).

The spelling of 21255240333 in words is "twenty-one billion, two hundred fifty-five million, two hundred forty thousand, three hundred thirty-three".