21111425521 has 8 divisors (see below), whose sum is σ = 22286602080. Its totient is φ = 19942653888.

The previous prime is 21111425459. The next prime is 21111425551. The reversal of 21111425521 is 12552411112.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21111425521 - 2⁹ = 21111425009 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21111425551) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1594456 + ... + 1607641.

It is an arithmetic number, because the mean of its divisors is an integer number (2785825260).

Almost surely, 2^21111425521 is an apocalyptic number.

It is an amenable number.

21111425521 is a deficient number, since it is larger than the sum of its proper divisors (1175176559).

21111425521 is a wasteful number, since it uses less digits than its factorization.

21111425521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3202463.

The product of its digits is 800, while the sum is 25.

Adding to 21111425521 its reverse (12552411112), we get a palindrome (33663836633).

The spelling of 21111425521 in words is "twenty-one billion, one hundred eleven million, four hundred twenty-five thousand, five hundred twenty-one".