21143240321 has 16 divisors (see below), whose sum is σ = 24299409024. Its totient is φ = 18021099264.

The previous prime is 21143240297. The next prime is 21143240347. The reversal of 21143240321 is 12304234112.

It is not a de Polignac number, because 21143240321 - 2²² = 21139046017 is a prime.

It is a super-2 number, since 2×21143240321² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21143210321) 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 15 ways as a sum of consecutive naturals, for example, 3917801 + ... + 3923193.

It is an arithmetic number, because the mean of its divisors is an integer number (1518713064).

Almost surely, 2^21143240321 is an apocalyptic number.

It is an amenable number.

21143240321 is a deficient number, since it is larger than the sum of its proper divisors (3156168703).

21143240321 is a wasteful number, since it uses less digits than its factorization.

21143240321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8440.

The product of its (nonzero) digits is 1152, while the sum is 23.

Adding to 21143240321 its reverse (12304234112), we get a palindrome (33447474433).

The spelling of 21143240321 in words is "twenty-one billion, one hundred forty-three million, two hundred forty thousand, three hundred twenty-one".