21002455255 has 8 divisors (see below), whose sum is σ = 26072013600. Its totient is φ = 16222586016.

The previous prime is 21002455247. The next prime is 21002455283. The reversal of 21002455255 is 55255420012.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21002455255 - 2³ = 21002455247 is a prime.

It is a super-2 number, since 2×21002455255² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 72422115 + ... + 72422404.

It is an arithmetic number, because the mean of its divisors is an integer number (3259001700).

Almost surely, 2^21002455255 is an apocalyptic number.

21002455255 is a deficient number, since it is larger than the sum of its proper divisors (5069558345).

21002455255 is a wasteful number, since it uses less digits than its factorization.

21002455255 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 144844553.

The product of its (nonzero) digits is 20000, while the sum is 31.

Adding to 21002455255 its reverse (55255420012), we get a palindrome (76257875267).

The spelling of 21002455255 in words is "twenty-one billion, two million, four hundred fifty-five thousand, two hundred fifty-five".