21243015366 has 32 divisors (see below), whose sum is σ = 43634354400. Its totient is φ = 6890507520.

The previous prime is 21243015323. The next prime is 21243015389. The reversal of 21243015366 is 66351034212.

It is a super-2 number, since 2×21243015366² (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 15 ways as a sum of consecutive naturals, for example, 15301 + ... + 206688.

It is an arithmetic number, because the mean of its divisors is an integer number (1363573575).

Almost surely, 2^21243015366 is an apocalyptic number.

21243015366 is an abundant number, since it is smaller than the sum of its proper divisors (22391339034).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21243015366 is a wasteful number, since it uses less digits than its factorization.

21243015366 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 222424.

The product of its (nonzero) digits is 25920, while the sum is 33.

Adding to 21243015366 its reverse (66351034212), we get a palindrome (87594049578).

The spelling of 21243015366 in words is "twenty-one billion, two hundred forty-three million, fifteen thousand, three hundred sixty-six".