21035210121 has 12 divisors (see below), whose sum is σ = 30957479748. Its totient is φ = 13758879264.

The previous prime is 21035210089. The next prime is 21035210159. The reversal of 21035210121 is 12101253012.

21035210121 is a `hidden beast` number, since 21 + 0 + 3 + 521 + 0 + 121 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 15960784896 + 5074425225 = 126336^2 + 71235^2 .

It is not a de Polignac number, because 21035210121 - 2⁵ = 21035210089 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21035210094 and 21035210103.

It is not an unprimeable number, because it can be changed into a prime (21035210191) 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 11 ways as a sum of consecutive naturals, for example, 22049010 + ... + 22049963.

It is an arithmetic number, because the mean of its divisors is an integer number (2579789979).

Almost surely, 2^21035210121 is an apocalyptic number.

It is an amenable number.

21035210121 is a deficient number, since it is larger than the sum of its proper divisors (9922269627).

21035210121 is a wasteful number, since it uses less digits than its factorization.

21035210121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 44099032 (or 44099029 counting only the distinct ones).

The product of its (nonzero) digits is 120, while the sum is 18.

Adding to 21035210121 its reverse (12101253012), we get a palindrome (33136463133).

The spelling of 21035210121 in words is "twenty-one billion, thirty-five million, two hundred ten thousand, one hundred twenty-one".