21115334510021 has 8 divisors (see below), whose sum is σ = 21844504481688. Its totient is φ = 20396362720000.

The previous prime is 21115334509991. The next prime is 21115334510041. The reversal of 21115334510021 is 12001543351112.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 9547105045921 + 11568229464100 = 3089839^2 + 3401210^2 .

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 21115334510021 - 2⁶ = 21115334509957 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21115334510041) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2549541200 + ... + 2549549481.

It is an arithmetic number, because the mean of its divisors is an integer number (2730563060211).

Almost surely, 2^{21115334510021} is an apocalyptic number.

It is an amenable number.

21115334510021 is a deficient number, since it is larger than the sum of its proper divisors (729169971667).

21115334510021 is a wasteful number, since it uses less digits than its factorization.

21115334510021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5099090823.

The product of its (nonzero) digits is 3600, while the sum is 29.

Adding to 21115334510021 its reverse (12001543351112), we get a palindrome (33116877861133).

The spelling of 21115334510021 in words is "twenty-one trillion, one hundred fifteen billion, three hundred thirty-four million, five hundred ten thousand, twenty-one".