21051113420 has 24 divisors (see below), whose sum is σ = 44932051248. Its totient is φ = 8282404800.

The previous prime is 21051113417. The next prime is 21051113437. The reversal of 21051113420 is 2431115012.

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 = 21051113392 and 21051113401.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 8626286 + ... + 8628725.

It is an arithmetic number, because the mean of its divisors is an integer number (1872168802).

Almost surely, 2^21051113420 is an apocalyptic number.

21051113420 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21051113420 is an abundant number, since it is smaller than the sum of its proper divisors (23880937828).

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

21051113420 is a wasteful number, since it uses less digits than its factorization.

21051113420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17255081 (or 17255079 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 20.

Adding to 21051113420 its reverse (2431115012), we get a palindrome (23482228432).

The spelling of 21051113420 in words is "twenty-one billion, fifty-one million, one hundred thirteen thousand, four hundred twenty".