21531510022243 has 12 divisors (see below), whose sum is σ = 23338570932768. Its totient is φ = 19855304820000.

The previous prime is 21531510022213. The next prime is 21531510022261. The reversal of 21531510022243 is 34222001513512.

It is a happy number.

It is not a de Polignac number, because 21531510022243 - 2³⁷ = 21394071068771 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21531510022213) 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 11 ways as a sum of consecutive naturals, for example, 63725883 + ... + 64062868.

It is an arithmetic number, because the mean of its divisors is an integer number (1944880911064).

Almost surely, 2^{21531510022243} is an apocalyptic number.

21531510022243 is a deficient number, since it is larger than the sum of its proper divisors (1807060910525).

21531510022243 is a wasteful number, since it uses less digits than its factorization.

21531510022243 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 127789774 (or 127789761 counting only the distinct ones).

The product of its (nonzero) digits is 14400, while the sum is 31.

Adding to 21531510022243 its reverse (34222001513512), we get a palindrome (55753511535755).

The spelling of 21531510022243 in words is "twenty-one trillion, five hundred thirty-one billion, five hundred ten million, twenty-two thousand, two hundred forty-three".