21200120971 has 2 divisors, whose sum is σ = 21200120972. Its totient is φ = 21200120970.

The previous prime is 21200120957. The next prime is 21200120989. The reversal of 21200120971 is 17902100212.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21200120971 - 2²³ = 21191732363 is a prime.

It is not a weakly prime, because it can be changed into another prime (21200120171) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10600060485 + 10600060486.

It is an arithmetic number, because the mean of its divisors is an integer number (10600060486).

Almost surely, 2^21200120971 is an apocalyptic number.

21200120971 is a deficient number, since it is larger than the sum of its proper divisors (1).

21200120971 is an equidigital number, since it uses as much as digits as its factorization.

21200120971 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 504, while the sum is 25.

The spelling of 21200120971 in words is "twenty-one billion, two hundred million, one hundred twenty thousand, nine hundred seventy-one".