21243240615 has 16 divisors (see below), whose sum is σ = 34325714016. Its totient is φ = 11217552000.

The previous prime is 21243240607. The next prime is 21243240617. The reversal of 21243240615 is 51604234212.

It is not a de Polignac number, because 21243240615 - 2³ = 21243240607 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21243240617) 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, 7009456 + ... + 7012485.

It is an arithmetic number, because the mean of its divisors is an integer number (2145357126).

Almost surely, 2^21243240615 is an apocalyptic number.

21243240615 is a deficient number, since it is larger than the sum of its proper divisors (13082473401).

21243240615 is a wasteful number, since it uses less digits than its factorization.

21243240615 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14022050.

The product of its (nonzero) digits is 11520, while the sum is 30.

Adding to 21243240615 its reverse (51604234212), we get a palindrome (72847474827).

The spelling of 21243240615 in words is "twenty-one billion, two hundred forty-three million, two hundred forty thousand, six hundred fifteen".