21420310121 has 16 divisors (see below), whose sum is σ = 25055606400. Its totient is φ = 17929029888.

The previous prime is 21420310103. The next prime is 21420310129. The reversal of 21420310121 is 12101302412.

It is a de Polignac number, because none of the positive numbers 2^k-21420310121 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21420310121.

It is not an unprimeable number, because it can be changed into a prime (21420310129) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2466575 + ... + 2475243.

It is an arithmetic number, because the mean of its divisors is an integer number (1565975400).

Almost surely, 2^21420310121 is an apocalyptic number.

It is an amenable number.

21420310121 is a deficient number, since it is larger than the sum of its proper divisors (3635296279).

21420310121 is an equidigital number, since it uses as much as digits as its factorization.

21420310121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16928.

The product of its (nonzero) digits is 96, while the sum is 17.

Adding to 21420310121 its reverse (12101302412), we get a palindrome (33521612533).

The spelling of 21420310121 in words is "twenty-one billion, four hundred twenty million, three hundred ten thousand, one hundred twenty-one".