21103212199961 has 2 divisors, whose sum is σ = 21103212199962. Its totient is φ = 21103212199960.

The previous prime is 21103212199913. The next prime is 21103212200029. The reversal of 21103212199961 is 16999121230112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20642992423936 + 460219776025 = 4543456^2 + 678395^2 .

It is a cyclic number.

It is not a de Polignac number, because 21103212199961 - 2⁶ = 21103212199897 is a prime.

It is not a weakly prime, because it can be changed into another prime (21103212198961) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10551606099980 + 10551606099981.

It is an arithmetic number, because the mean of its divisors is an integer number (10551606099981).

Almost surely, 2^{21103212199961} is an apocalyptic number.

It is an amenable number.

21103212199961 is a deficient number, since it is larger than the sum of its proper divisors (1).

21103212199961 is an equidigital number, since it uses as much as digits as its factorization.

21103212199961 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 104976, while the sum is 47.

The spelling of 21103212199961 in words is "twenty-one trillion, one hundred three billion, two hundred twelve million, one hundred ninety-nine thousand, nine hundred sixty-one".