21102010121 has 8 divisors (see below), whose sum is σ = 22493262600. Its totient is φ = 19727419648.

The previous prime is 21102010117. The next prime is 21102010141. The reversal of 21102010121 is 12101020112.

It can be written as a sum of positive squares in 4 ways, for example, as 3230330896 + 17871679225 = 56836^2 + 133685^2 .

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 21102010121 - 2² = 21102010117 is a prime.

It is a super-2 number, since 2×21102010121² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21102010141) 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, 4162886 + ... + 4167951.

It is an arithmetic number, because the mean of its divisors is an integer number (2811657825).

Almost surely, 2^21102010121 is an apocalyptic number.

It is an amenable number.

21102010121 is a deficient number, since it is larger than the sum of its proper divisors (1391252479).

21102010121 is a wasteful number, since it uses less digits than its factorization.

21102010121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8331003.

The product of its (nonzero) digits is 8, while the sum is 11.

Adding to 21102010121 its reverse (12101020112), we get a palindrome (33203030233).

Subtracting from 21102010121 its reverse (12101020112), we obtain a palindrome (9000990009).

The spelling of 21102010121 in words is "twenty-one billion, one hundred two million, ten thousand, one hundred twenty-one".