21097271941 has 2 divisors, whose sum is σ = 21097271942. Its totient is φ = 21097271940.

The previous prime is 21097271903. The next prime is 21097272011. The reversal of 21097271941 is 14917279012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20347881316 + 749390625 = 142646^2 + 27375^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21097271941 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21097271141) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10548635970 + 10548635971.

It is an arithmetic number, because the mean of its divisors is an integer number (10548635971).

Almost surely, 2^21097271941 is an apocalyptic number.

It is an amenable number.

21097271941 is a deficient number, since it is larger than the sum of its proper divisors (1).

21097271941 is an equidigital number, since it uses as much as digits as its factorization.

21097271941 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 63504, while the sum is 43.

The spelling of 21097271941 in words is "twenty-one billion, ninety-seven million, two hundred seventy-one thousand, nine hundred forty-one".