21221057406473 has 2 divisors, whose sum is σ = 21221057406474. Its totient is φ = 21221057406472.

The previous prime is 21221057406469. The next prime is 21221057406539. The reversal of 21221057406473 is 37460475012212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18041494110784 + 3179563295689 = 4247528^2 + 1783133^2 .

It is a cyclic number.

It is not a de Polignac number, because 21221057406473 - 2² = 21221057406469 is a prime.

It is not a weakly prime, because it can be changed into another prime (21221057406673) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10610528703236 + 10610528703237.

It is an arithmetic number, because the mean of its divisors is an integer number (10610528703237).

Almost surely, 2^{21221057406473} is an apocalyptic number.

It is an amenable number.

21221057406473 is a deficient number, since it is larger than the sum of its proper divisors (1).

21221057406473 is an equidigital number, since it uses as much as digits as its factorization.

21221057406473 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 564480, while the sum is 44.

The spelling of 21221057406473 in words is "twenty-one trillion, two hundred twenty-one billion, fifty-seven million, four hundred six thousand, four hundred seventy-three".