21101302121 has 2 divisors, whose sum is σ = 21101302122. Its totient is φ = 21101302120.

The previous prime is 21101302099. The next prime is 21101302127. The reversal of 21101302121 is 12120310112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21019200400 + 82101721 = 144980^2 + 9061^2 .

It is a cyclic number.

It is not a de Polignac number, because 21101302121 - 2²² = 21097107817 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21101302096 and 21101302105.

It is not a weakly prime, because it can be changed into another prime (21101302127) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10550651060 + 10550651061.

It is an arithmetic number, because the mean of its divisors is an integer number (10550651061).

Almost surely, 2^21101302121 is an apocalyptic number.

It is an amenable number.

21101302121 is a deficient number, since it is larger than the sum of its proper divisors (1).

21101302121 is an equidigital number, since it uses as much as digits as its factorization.

21101302121 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 24, while the sum is 14.

Adding to 21101302121 its reverse (12120310112), we get a palindrome (33221612233).

The spelling of 21101302121 in words is "twenty-one billion, one hundred one million, three hundred two thousand, one hundred twenty-one".