21000541697 has 2 divisors, whose sum is σ = 21000541698. Its totient is φ = 21000541696.

The previous prime is 21000541687. The next prime is 21000541703. The reversal of 21000541697 is 79614500012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 10768005361 + 10232536336 = 103769^2 + 101156^2 .

It is a cyclic number.

It is not a de Polignac number, because 21000541697 - 2²⁴ = 20983764481 is a prime.

It is not a weakly prime, because it can be changed into another prime (21000541607) 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, 10500270848 + 10500270849.

It is an arithmetic number, because the mean of its divisors is an integer number (10500270849).

Almost surely, 2^21000541697 is an apocalyptic number.

It is an amenable number.

21000541697 is a deficient number, since it is larger than the sum of its proper divisors (1).

21000541697 is an equidigital number, since it uses as much as digits as its factorization.

21000541697 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 15120, while the sum is 35.

The spelling of 21000541697 in words is "twenty-one billion, five hundred forty-one thousand, six hundred ninety-seven".