21243531255 has 16 divisors (see below), whose sum is σ = 34026259680. Its totient is φ = 11317680128.

The previous prime is 21243531251. The next prime is 21243531263. The reversal of 21243531255 is 55213534212.

It is a cyclic number.

It is not a de Polignac number, because 21243531255 - 2² = 21243531251 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21243531251) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 748302 + ... + 776171.

It is an arithmetic number, because the mean of its divisors is an integer number (2126641230).

Almost surely, 2^21243531255 is an apocalyptic number.

21243531255 is a deficient number, since it is larger than the sum of its proper divisors (12782728425).

21243531255 is a wasteful number, since it uses less digits than its factorization.

21243531255 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1525410.

The product of its digits is 36000, while the sum is 33.

The spelling of 21243531255 in words is "twenty-one billion, two hundred forty-three million, five hundred thirty-one thousand, two hundred fifty-five".