21223121420 has 48 divisors (see below), whose sum is σ = 46035268608. Its totient is φ = 8210220480.

The previous prime is 21223121401. The next prime is 21223121431. The reversal of 21223121420 is 2412132212.

It is a super-3 number, since 3×21223121420³ (a number of 32 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a junction number, because it is equal to n+sod(n) for n = 21223121392 and 21223121401.

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, 1058327 + ... + 1078193.

It is an arithmetic number, because the mean of its divisors is an integer number (959068096).

Almost surely, 2^21223121420 is an apocalyptic number.

21223121420 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21223121420 is an abundant number, since it is smaller than the sum of its proper divisors (24812147188).

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

21223121420 is a wasteful number, since it uses less digits than its factorization.

21223121420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21630 (or 21628 counting only the distinct ones).

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

Adding to 21223121420 its reverse (2412132212), we get a palindrome (23635253632).

The spelling of 21223121420 in words is "twenty-one billion, two hundred twenty-three million, one hundred twenty-one thousand, four hundred twenty".