21403221221 has 48 divisors (see below), whose sum is σ = 24073201152. Its totient is φ = 19000396800.

The previous prime is 21403221211. The next prime is 21403221223. The reversal of 21403221221 is 12212230412.

It is not a de Polignac number, because 21403221221 - 2⁶ = 21403221157 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21403221193 and 21403221202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21403221223) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 108645695 + ... + 108645891.

It is an arithmetic number, because the mean of its divisors is an integer number (501525024).

Almost surely, 2^21403221221 is an apocalyptic number.

It is an amenable number.

21403221221 is a deficient number, since it is larger than the sum of its proper divisors (2669979931).

21403221221 is a wasteful number, since it uses less digits than its factorization.

21403221221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 510 (or 493 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 20.

Adding to 21403221221 its reverse (12212230412), we get a palindrome (33615451633).

It can be divided in two parts, 2140322 and 1221, that multiplied together give a palindrome (2613333162).

The spelling of 21403221221 in words is "twenty-one billion, four hundred three million, two hundred twenty-one thousand, two hundred twenty-one".