21123201420 has 72 divisors (see below), whose sum is σ = 67842762624. Its totient is φ = 5301508608.

The previous prime is 21123201413. The next prime is 21123201427. The reversal of 21123201420 is 2410232112.

It is a happy number.

21123201420 is a `hidden beast` number, since 2 + 11 + 232 + 0 + 1 + 420 = 666.

It is an interprime number because it is at equal distance from previous prime (21123201413) and next prime (21123201427).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 21123201393 and 21123201402.

It is not an unprimeable number, because it can be changed into a prime (21123201427) 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 23 ways as a sum of consecutive naturals, for example, 3448444 + ... + 3454563.

It is an arithmetic number, because the mean of its divisors is an integer number (942260592).

Almost surely, 2^21123201420 is an apocalyptic number.

21123201420 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21123201420 is an abundant number, since it is smaller than the sum of its proper divisors (46719561204).

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

21123201420 is a wasteful number, since it uses less digits than its factorization.

21123201420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6903039 (or 6903034 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

Adding to 21123201420 its reverse (2410232112), we get a palindrome (23533433532).

The spelling of 21123201420 in words is "twenty-one billion, one hundred twenty-three million, two hundred one thousand, four hundred twenty".