21202032121 has 2 divisors, whose sum is σ = 21202032122. Its totient is φ = 21202032120.

The previous prime is 21202032107. The next prime is 21202032169. The reversal of 21202032121 is 12123020212.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16676106496 + 4525925625 = 129136^2 + 67275^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21202032121 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21202032095 and 21202032104.

It is not a weakly prime, because it can be changed into another prime (21202032101) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10601016060 + 10601016061.

It is an arithmetic number, because the mean of its divisors is an integer number (10601016061).

Almost surely, 2^21202032121 is an apocalyptic number.

It is an amenable number.

21202032121 is a deficient number, since it is larger than the sum of its proper divisors (1).

21202032121 is an equidigital number, since it uses as much as digits as its factorization.

21202032121 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 96, while the sum is 16.

Adding to 21202032121 its reverse (12123020212), we get a palindrome (33325052333).

The spelling of 21202032121 in words is "twenty-one billion, two hundred two million, thirty-two thousand, one hundred twenty-one".