21121210211953 has 2 divisors, whose sum is σ = 21121210211954. Its totient is φ = 21121210211952.

The previous prime is 21121210211939. The next prime is 21121210211963. The reversal of 21121210211953 is 35911201212112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15582022023649 + 5539188188304 = 3947407^2 + 2353548^2 .

It is a cyclic number.

It is not a de Polignac number, because 21121210211953 - 2⁹ = 21121210211441 is a prime.

It is a super-2 number, since 2×21121210211953² (a number of 27 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21121210211963) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10560605105976 + 10560605105977.

It is an arithmetic number, because the mean of its divisors is an integer number (10560605105977).

Almost surely, 2^{21121210211953} is an apocalyptic number.

It is an amenable number.

21121210211953 is a deficient number, since it is larger than the sum of its proper divisors (1).

21121210211953 is an equidigital number, since it uses as much as digits as its factorization.

21121210211953 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2160, while the sum is 31.

The spelling of 21121210211953 in words is "twenty-one trillion, one hundred twenty-one billion, two hundred ten million, two hundred eleven thousand, nine hundred fifty-three".